I've played Pokemon World Online, which had elements from up to Gen 4, so I haven't been in a total vacuum. Fan-made is better than nothing.
As for the Pokemon RP system, using all the elements from the game proved to be a bit too complicated to put together a decent dice-based system. At that point, you're better off just playing an online battle simulator. Now, Ringman and I have discussed simpler systems, one which would involve a program where you put in your stats and it calculates hits. Another simpler system would be a variation on Wushu, and since we already have the system, that might be easier to work with.
As for Mega Evolutions, I could incorporate that into the system pretty easily, but they would be basically just a new set of stats after the player announces that their Pokemon Mega Evolved.