Thinking about how fighting with a pole arm works. Great for the reach, but so many people don't let them get used when an enemy is adjacent. But how often does a spear get depicted as being used essentially as a quarterstaff with a pointy tip? So, I had this thought as someone who thinks that the quarterstaff is so under-powered.
Un-named Combat Feat
You are able to use a pole-arm as a double weapon without reach.
Prerequisites: Two-Weapon Fighting, Martial Weapon Proficiency
Effect: You are able to switch a pole-arm from a reach weapon to a double weapon using the standard rules for both.
Obviously needs some work on the formatting, but my mind isn't on it fully and just want to make sure that I'm not wasting my time on this if it is already done.
There is this: Spear Dancing Style.
It's significantly better than what Polearm Masters get at level 2.
There is this: Spear Dancing Style.
This seems like what I had thought. Thanks
Spear Dancing Style loses both reach and brace? Why not just use, you know, anything else at that point. A polearm without reach is effectively useless. Choose literally any other weapon and any other feat specific to your chosen weapon. It gives it the double weapon quality, meaning you have to enchant both ends separately. Gross. Can't even use it effectively with Shield Brace anymore. It has TWF as a prerequisite, which is so disgusting unless it's the focus of your character.
The Polearm Master level 2 ability is way better, in my opinion, as it specifically does NOT give your polearm the double weapon quality, nor does it eliminate reach and brace. And you don't have to ever touch TWF, immediately better in every way.
Spear Dancing Style is excellent if you didn't actually want to use a polearm at all, and instead were planning a double weapon build from the get go, but wanted a polearm for flavor reasons.
Anyone with a polearm can just take Improved Unarmed Strike and kick whoever gets too close. Life isn't hard in fantasy land.
A polearm with reach is effectively useless when you're cornered; that sounds like a good time to have Spear Dancing Style. Plus, you don't have to be a polearm master (or a fighter at all).
In practice, though, it's a lot of feats to be good at both using a polearm and two-weapon fighting with a double weapon, especially since half of your TWF won't be boosted at all by weapon enhancements. Much easier to simply specialize in the reach stuff and keep a backup non-reach weapon (cestus and armor spikes are nice for this) for when you get cornered. But thematically, you can make an effective SDS character that sticks with the one weapon.
Armor Spikes, good call by the way, no feats, just awesome as long as you can wear armor.
Improved Unarmed Strike, one feat, your kick does the same damage as the light mace end of your spear dancing double weapon.
Upsetting Shield Style, one feat, shield bash with a buckler, which you can already use with a polearm.
Dare I say it... Bladed Brush Combat, two feats, you can switch grip on your glaive to use it without reach, but it can still be used with reach if you need or desire. Plus, weapon focus is probably the best prerequisite you can ask for. You have to use a glaive, though.
Shield Brace, two feats, allows you to use a polearm and a shield. You can bash with a shield in close, poke at distance with your polearm that still has reach. Plus, shield focus and a heavy shield gives you a +3 AC whenever you don't use it to bash.
Best part: none of these require TWF...
The weapon trick (polearm) feat gives other ways of dealing with being too close for a reach weapon too. It's just that spear dancing style was almost exactly what the OP asked for.