Place your Bets! Guess what the next Everdrive will be....

Improve existing Everdrives is a good option, too. I can't imagine the features that can be added or improved, so I'm curious about that.
About CD emulators, what it's strange for me is that nobody have cared about making one.

 

CD-ROM replacements are probably more complicated to do. There are different interfaces on different systems. Maybe someday someone will do it. I know I would like to see it done for various CD based consoles. PS1 above all for reliability.