I tried an actual Pokémon D&D Style RP once, my sis tried to run it from an anime based tabletop game called Big Eyes Small Mouth for the characters, and actual Pokémon game stats and calculations for the Pokémon.  However, it was the latter that proved problematic.  You don't really realize how much work goes into calculating each and every thing about Pokémon until you actually try to calculate the stuff yourself for an RP.  Not even our usual GM could get it to work.