I could see Exeggutor, and a Ghost-type Marowak's always seemed a no-brainer for Mega Evolution, but I really doubt it.
I know Masuda said that they're not really thinking about Mega Evolution right now, but I really doubt that. It's probably something they want to save for remakes. Other than the nostalgia factor and the occasional new form, there's not really a whole lot to market remakes on: you can't just introduce brand-new Pokemon mid-generation because of compatibility issues. Mega Evolution lets them have new Pokemon to sell the game without actually introducing new Pokemon. When DPP is remade, we'll probably get some new forms for Dialga/Palkia/Giratina, and then a plethora of Mega Evolutions for other Pokemon.
