BladedFlower
Archolite
Alas, I too have the Aggronite. Out of curiosity, why exactly do you want Mega Tyranitar? Just for coolness factor? : P
Not really, you see I only have the stone but as for Aggron I don't have the pokemon. Plus I like Tyranitar. I've loved him/her since the Celebi movie.
3nodding Oh yeah, I know as well as anyone how cool T-Tar is.
pirate .
And yeah, Y gives you Aggronite but you find wild Pupitars. And X gives you Tyranitarite, but only gives you wild Lairons or whichever evolution it is that you find.
Trading evolution stones is always difficult. I wish you luck with this. You could always get Pokemon X to get all the Pokemon that are Version exclusive and have another run through the Story Mode. I've considered it myself.