I don't know about coverting them into an ISO. I think that 500kb's or thereabouts is about as small as you're going to get with these. Most I have downloaded have averaged about 500kbs. Wait, you said 500mbs! That's huge, I think you just misquoted the file size and meant kb's instead of mbs. But anyway, to covert you just have to go back a page or a few pages and find that program we had posted, think it's UNECM.exe, just google search it and download it. It's a small file if I recall. Then any files that are une.bin or whatever, just copy that file and paste it right on top of that une.exe file and it should start covering them. Some roms on some of these websites simply don't work with this emulator, or with my phone or something. I'm sure it'll be much better in a couple of weeks.
I'm trying out different games, trying to post which ones will work. As far as any roms and such, if you own the original game...blah...and need help with a particular download that I might have found just PM me. I have Marvel Heroes vs Capcom working pretty darn well. I'm currently trying to get The Last Blade by SNK to work, man that is one of the all-time best fighting games ever.