Well, there isn't any definitive info on it since the prototype is still being worked on. Any news about it would be at http://www.vgwiz.com/.

It started as an idea for a development cart, and many other people want it to be a universal cart to run any game (which is more demanding, of course, with all the various mappers 'n such). I'm not sure which approach they're taking, but it should be cool either way. I just want to run my stuff on my NES! heheh :)

I think it should be able to do 8KB PRG switching, but I haven't seen the schematic so I'm not totally sure. You could ask them about it on the VGWiz forum.