race: using the race creation guidelines from the advanced race guide to make an anthropomorphic human/animal race like the teenage mutant ninja turtles or some other human/animal hybrid.
setting: sci-fi/future. with the technology guide from paizo, there's ways to model far future campaigns. TMNT had a dimensional/time travel sourcebook. I'm thinking something like that where the mutants are created and used for space exploration teams by society in 3014/3015, or an After The Bomb type setting where radiation and genetic engineering have created these mutants and the human population has been decimated.
classes: since its sci fi/future, its harder to rationalize the magic, but i think mixing some sorcery in and stuff in the future would be fun. Easiest to integrate are nonmagical base classes: fighter, rogue. if we go towards a more Warhammer 40k universe type feel, then magic isn't that rare, if we go more gritty, then we can push things with semi-magical classes like ranger, barbarian, monk, paladin, and just tone down the magic inherent or go with archetypes that replace the spell-casting and supernatural abilities ( non-magic ranger, martial artist monk, i'm sure there's one for paladin too? ) , expert could be expanded to a PC class with technology crafting bonus feats and abilities. I'm in favor of a magical sci-fi romp through time and space.
houserule: if anyone goes evasion, i'd like to try out a house rule that evasion is a 1/day daily at the level its attained ( +1 /day /3 levels beyond ) where on they take 50% less damage on a successufl reflex save. [ so 1/4 on a successful save, for the Improved Evasion it would also be usable to get 1/2 damage on a failed save, but its still a consumable ability ]