Legends Walk! by Tim Gray is a fairly massive (169 pages!) shareware roleplaying game about superheroes in a modern setting with their powers derived from mythological sources. A lot of work has gone into this, with detailed descriptions of gods and the powers each one can provide, lots of background, detailed rules for combat and everything else, a skill list, GMing advice – there’s a professional level of detail here.
The mechanics use a simple dice pool (similar to something I thought of myself, actually), with nice explanations of the design decisions for certain features (why dice don’t “explode” in the default rules, even though it’s suggested as an option). And the attributes are a bit peculiar, with intelligence split into “wisdom” and “ingenuity” (perhaps to simulate differences between specific gods?). But very impressive overall.
I think I’ll still go with Powergame this Bigor, though, because preversely, because it’s so much shorter and fannishly presented, it’s much simpler to wrap my head around.