record roms in a flah cartdridge


Few years ago I read some docs talking about record rom files in a cartdrige based in flash memory or something similar.It was very interesting...but I lost it. The doc give information to build a conector from megadrive to pc and how to build the cartdridge to record the roms.

Somebody have this kind of info?

Somebody have this docs?

Or someboy kwows a way to build something similar?

Or this kind of cartdridge is sold in some place?

It would be a dream!