Mega Evolutions on Non-Fully Evolved Pokemon completely defeat the purpose of a Mega Evolution. The whole point of Mega Evolution is basically going beyond the maximum and releasing a new form. Pikachu is not the "maximum" of that species, unless it is carrying a specific item, and using said item means Pikachu can't Mega Evolve. Kind of contradictory situation wouldn't you say?
Raichu is possible, but I'm not confident of making a claim either way. --- www.rpgdl.com The site Meeple argues at for too much of his life!
Raichu has never stepped up and done anything of note. I'd be glad to be wrong, but it's always been (and always will be) a loser. --- Check out our Persona 3 Let's Play! http://www.youtube.com/watch?v=J_Wlm6CGZV8
Gamefreak does not like Raichu. So i would bet on MegaPikachu if anything at all. --- Jaricko - Official Venustoise of the omniverse / bacon in the fridge for all those who cry out in hunger of the Gamefaq's 3ds boards.