There's more deities than those two who give madness. Courtesy of Archives of Nethys: Abhoth, Ajids, Alichino, Atlach-Nacha, Azathoth, Calcabrina, Chucaro, Cthulhu, Eaqueo, Ghatanothoa, Groetus, Gyronna, Haggakal, Hastrikhal, Laivatiniel, Lamashtu, Ose, Osolmyr, Pirias, Set, Shivaska, Shyka, Sifkesh, Sivanah, The Lantern King, The Lost Prince, Trelmarixian, Tsukiyo, Zura.
Chucaro is actually good-aligned. The Good/azata subdomain is OK for a melee cleric. Shyka is true neutral and gives the Destruction domain if you feel like smiting people.
Even without domains there are offensive spells on the cleric list which have saves. Burst of Radiance is a good one, Hold Person, several variants on Command, curses etc.
As tempting as it sounds, I wouldnt do the longspear + conducting thing.... yes you get reach, but you'll have to hit regular AC instead of touch.
An enhanced Wizards Hook + Lunging Spell Touch is a far better option. Keeps you hitting touch AC with a nice bonus, Plus you dont have to burn 2 uses each time.
Take wisdom as your primary stat and try to worship a neutral god I'm not sure if the one you just mentioned is neutral. If so Great! if not it's not the end of the world.
Place your lvl 1 stats as follows:
Str 14 dex 12 con 17 int 10 wis 20 cha 14
Take the trickery and madness domain no problem.
Channel negative energy. (You will need to prepare cures)
feats:
1 channel smite, guided hand (human bonus feat)
3 combat reflexes
5 power attack
Now you attack using your wisdom rather than strength, and your strength is decent enough to give some damage.
Your weapon is quite important it should have the conductive property, but also properties that give ectra d6 to damage specifically shock and frost, and wear deliquessent gloves.
Starting lvl 8 prepare greater magic weapon to give yourself the actual enchancement bonus.
You really want a belt of physical perfection +2 as soon as you can afford it.
There is an ioun stone that gives profficiency with a weapon, get it and a better weapon before you seriously invest, but have a spare longspear just in case.
On your turn when you yourself actually attack and it is an important fight channel smite, you have no other uses for your channels, and you must take the feat anyways, so use what you got.
After lvl 5 take spell casting feats, whatever picks your fancy. Spell pen, and greater spell pen are good, reach spell is good in combo with say bestow curse. Experiment, have fun and retrain your regrets.
EDIT: I just remembered guided hand only works with the deities favored weapon, take someone who gives madness and a reach weapon, or bite the bullet and become a separatist.
I certainly think it is fine to have a reach cleric without any melee focused domains. I think it is a mistake to consider a reach cleric melee focused however. Your focus should be your main job in the party, which in this case is battlefield control (via debuffing). Melee is what you do either a) when they provoke an AoO (and this is another aspect of battlefield control more than focusing on damage) and b) when you don't have anything that is actually important to do, because your main job is already taken care of. Having enough attack abilities that the foe has to worry about your threatened area is important, but actually doing damage should be a secondary concern, it can be more of a 'win' if they avoid your threatened area than if they don't and you damage them.
Madness domain is pretty awesome, and certainly great for debuffing. Personally, given that both of the madness domain abilities are standard actions as well as most of your spells, I'd be looking for domain powers that were swift or immediate actions for your second domain, or out-of-combat utility if you can find something good. You only have so many standard actions.
One possibility to deal with not having a domains you like is taking an archetype that limits you to only a single domain, evangelist is usually considered a pretty strong option. It is more suited to the support role than the controller role, but once you reach 7th you will be able to inspire courage as a move and still use your standard for a control action. This would work best if you had some sort of mount though since that would also let you position yourself for a good threatened area.
Growth is a nice domain. I'd probably rather have feather for the perception bonus and animal companion, but swift action enlarge is awesome.
I've never gone for using acrobatics to maneuver a threatened area around with a reach cleric. Between ACP and moderate DEX I've never felt it something to be counted on, and skill points are already few and far between. I find positioning early in combat to protect the 'back line' and then some adjustments, and on occasion taking an AoO in the teeth if moving is important enough to be preferable. And I find that the mobility of being able to move a significant distance (at least 40' with most mounts) is better, especially for those emergency 'get this character a heal spell now' situations. A mount with reach (I like the axebeak when taking the feather domain anyway) also doubles your 'threatened area threat', and that is worth the trade. Plus, remember the mount can make a single attack before you move (if it is only making a single move), which sometimes will take a threatening foe down.
In your case, being a debuffer makes it even less of a worry. After you hit them with a powerful debuff, you can go ahead and move away, knowing they aren't likely to hit you anyway, and you don't particularly need to 'lock them' down.
As far as light armor goes, it isn't wonderful particularly without a great DEX, but it isn't the end of the world either. Personally, I think inspire courage making the enemies dead faster is better than AC for keeping the HP up. Obviously a feat could fix this if desired, and you can't spend a feat to get inspire courage, of course if someone else wants to play a bard and embrace the support role the benefits immediately go away, but if the rest of your group wants to play strikers, it is probably worth the trade. And of course if you do want to go the tumble route, light armor is generally better for acrobatics anyway.
If you want to combo Madness Domain and melee combat in an awesome way, use Domain Strike. Unlike a Conductive weapon, you don't burn through uses/day like mad. You also don't need an unarmed strike build to use it well; you can reserve making actual unarmed strikes for when you need it, and use whatever other combat style you like otherwise. You could even dual wield weapon and fist if you wanted to.
To bump up the effectiveness of a melee Cleric, a single-level dip into a martial class can make a huge difference. Unchained Monk in particular stands out, though Urban Bloodrager and others can also be very useful. Unchained Monk wielding a Monk sword in two hands and making Stunning Fist and Domain Strike: Madness punches would be brutal.
Would madness/feather separatist work (also, how the hell would you roleplay it?)?I'm not 100% sure, but I think it would involve a feather boa.
Also, why specifically an axe beak?
It is a decent animal companion in its own right, the large/tall gives it reach, which works well with a reach build, and feather domain seems like it should pick a bird. Plus it reminds me of the video game Joust.
You are better off targetting touch AC IMO.... with a 3/4 BAB class especially.
For a cleric, as you level up hitting touch AC gets easier as opposed to harder vs regular AC.
Even in mid-high level games its common to see touch AC in the 15-18 range.