I recall a few months ago that someone said they used gestalt PCs, with the second class for some PCs being a "monster class".
For that poster, was this balanced against the other PCs that used normal gestalt rules? What was the party mix, and how did it all work out?
I was not said poster, but would like to hear the answer.
I have gestalted the level progression dragon class before (Green w/ Hexblade, very nasty).
The way I did it was overpowered, assuming you are using a Savage Species style level progression, I would only allow gestalt levels on the levels that grant Hit Dice. The other levels can be considered Level Adjustment. When I made the character originally, I gestalted every level, and felt the character was too powerful.
I currently have no players in my SCAP with monster hit dice, though we do have one githzerai, whose level adjustment we made into 1 (from a normal 2), that takes up both class slots at 1st level. I'm still not sure this was the proper way to do this, but is much more fair than allowing LA to gestalt fully. Which is why we changed the gith.
We have an ex-player that was a tiefling rogue/wizard. With only a +1 level adjustment, it seemed more balanced. and looking at the char sheet, I had allowed the LA to gestalt.
It is tricky when you throw in something like Gestalt with alternate rules like Monster PCs and LAs. I kind of wish I had ruled out non-standard races, but hindsight is 20/20.
-c
You can't really use level-adjustment-races and monster-races with standard gestalting. The problem is that both of these give you "levels" where you don't gain a Hit Die (including effects on Base Attack and Saves as well as Hit Points), unlike any real Class that you could take. When you Gestalt and allow a class to be taken on the "other" side, you're eliminating the entire penalty of the level-adjustment/lack-of-HD.
Likewise, you can't just divide the LA by 2 and say it's that number of levels of just being a monster. Functionally, there's very little difference between having a LA+2 race and then one level in each of two classes gestalted together, versus having an LA+2 race on one side and one level in each of two separate classes on the other side.
My husband and I have done a fair amount of gestalt-campaigning, and we never did come up with a way to use these sorts of races/monsters that came out balanced. The best option we came up with was to require that all the PCs have the same LA (everyone chooses an LA+1 race, or you can pick an LA+0 race but the DM adds some stuff to make it equivalent to the LA+1 races).