Check out this site. They sell Genesis flashcarts, I've been wanting to get one for a while but never got round to it, also I don't know if they are reliable (the site and the carts ).
If you can find it, you have to get Rock & Roll racing
<That's a point............seing as it is possible to rip data from a cartridge to your computer, would it technically be possible to do it the other way round? Of course, you'd need blank cartridges, they'd be hard to find!>
Just noticed they sell Snes copyboxes too, for cheap. I really love my copyboxes, emulation is cool, but nothing beats the real thing.