Unfortunately Chilly Willy seems to be inactive since 2015 (is everything ok with him/you)?
Instead of creating a new topic, I decided to reply to this one, completely aware that the last relevant post was in 2013.
So, my 2 cents on the subject:
- I recently discovered a tool called Screen Scraper that downloads almost every type of image you can think of (2d box, 3d box, cartridge, title/gameplay, screenshot, marquee, etc) for pretty much every game of every system, genesis/mega drive included, with the same name as the ROM.
- whatever image format would eventually be supported by custom or official firmware, we would "only" need a tool to convert the downloaded images to the required format, or some kind of script using the required programs to convert the images.
- One simple suggestion to what to display: an image on the right side of the screen, showing either the box art or the cartridge, or possibly a menu option to select between none, one of the two, or both (one above the other). Or even simpler, just modify the firmware so it changes the background to a background with the same name as the selected ROM (ex: background_romName.jpg) where the image format is a black image with the box/cartridge art on the right.