I'm playing in such a campaign right now. We're all githzerai, working on retaking the Gith homeworld from the wilderness and whatever threats we encounter along the way to 'civilization'.
The DM went a little crazy with UA rules options for the game - we're all gestalt characters, with full githzerai abilities (so we're +2 ECL). There are only three races - high githzerai (the default from the XPH), h'ranmar githzerai (beast-blooded, with some animal traits and a more physical bent), and duk'kar (mentally-focused, bred by the illithid for their tasty brains). I'm guessing some of the XPH races will show up as the game progresses, though - there have been hints of other sentient life around.
The group is comprised of...
- H'ranmar Fighter/Ranger // Psychic Warrior, the party tank
- H'ranmar Fighter // Adept, very much a cleric, with both warrior and healer abilities. The DM modified a couple of the Ardent mantles so that she's more capable in the healer's role, though I'm not sure exactly what he did to them.
- High Githzerai Fighter // Soulknife, the other tank. He didn't want to learn psionic powers, so he's playing a soulknife.
- High Githzerai Monk // Psion (Telepath), mostly focusing on her martial arts stuff.
- Duk'kar Githzerai Psion (Kineticist) // Monk, not really using his monk abilities at all; he's the group's blaster.
- Duk'kar Githzerai Scout // Psychic Warrior, a skirmishing combatant with a focus on ancient archaeology. Which makes her, though it hadn't occurred to me before, an albino version of Lara Croft.
We did tend to divide ourselves into traditional party roles - tank, healer, blaster, etc. Nobody's great at the rogue stuff, though the monks and scout are all decent at sneaking, nobody is any good at traps or investigation. No people person, either - the highest Charisma in the party is, I think, a 12, with no ranks in social skills.
Judging our abilities is kinda hard, since we're all gestalt with an ECL, which we haven't dealt with much before. We're pretty tough, though - we managed to beat an illithid and several supporting monsters (some grimlocks, two voidmind ogres, and a pair of dominated gith monks) when we had four class levels each. 'course, one of us died doing it, but I was still impressed.