Premise: Holy Vindicator stacks with ANY class that grants the channel energy class ability. What if you channel positive from one source and negative from another?
How about a Gnome Life Oracle 3/Cleric (neutral or evil god) 4/Holy Vindicator 10?
20 point buy:
Str 6
Dex 12
Con 14
Int 8
Wis 16
Cha 29 (19 +4 level +6 headband)
You're channelling positive energy at 7d6 13 times per day, negative at 8d6 with bloodrain plus 1d6 bleed plus sickened 15 times per day. The save DC is 28 with improved channel. You can do either of these in a standard burst, a cone or a line. Lame curse counteracts the low str. Extra revelation feat makes you crazy healer with life link, channel, and energy body as your revelations.
Channelling is the focus of the build, but of course you're a half-decent caster also, and nice ac due to the standard benefits of holy vindicator with heavy armor and vindicator's shield. If you combine pyromaniac with fire domain, you're a passable blaster as well.
You can make a more effective negative energy channeler by just going straight cleric/hv, but this lets you be pretty much an equal healer as a positive channelling cleric also.
I don't even really like it, but what's your opinion of the Holy Vindicator channel interpretation? Is it RAW? RAI?
It seems to be the RAW (otherwise the wording should be "any ONE class"), and since both oracle and HV came with the APG the designer should have been aware of that.
IMO It sounds ok, you trade max power per hit/novaing (7d6 instead of 10d6, 7th level spells instead of 9th spell slots) for versatility and more special abilities' uses per day and spells per day (not really that much, because HV only increases the caster level of One class).
I'm torn between taking the divine caster levels in oracle or cleric. I think you gotta go Oracle because of the charisma focus, but that costs you 2 more spell levels (depending on the level, with lower oracle spell progression and oracle 3 vs cleric 4) Either way I suppose you go pyromaniac and use flame strike as another nice option. With all those uses of channel, quick channel becomes a nice option too from UM.