Lately MESS has made huge progress on systems completely obscure like the hanimex pencil 2 (many thanks to all implied... I'm after the carts so as to try to contribute dumps). However, perhaps this one might make you remember a few things:

does anyone remember the venerable HMG 7900 with it's 10 or so games?

http://www.old-computers.com/museum/computer.asp?c=696&st=2

this one uses some pretty peculiar hardware (I one read back in the day that efforts were made to dump components, I've no idea if they met success or not).
Might anyone in the mess project have those items in their collection?