I was lurking on /vp/ (the Pokemon board on 4chan) and the ROMs are apparently 256mb each. Also there's someone called "Koby", he's a Japanese fellow who is dumping the ROMs, well they say so anyway. There's been a few images from his blog of him playing it on Desmume, and they've been posted on 4chan but I can't find the link. I hope they get dumped soon.
Oh and there's been alot (I mean, ALOT) of fake ROMs out there. From Cory in the House to a .rar full of pornographic images. So yeah, just a heads up.