Dear Arye,
First of all, welcome to the forum.
If I understood your application, maybe you don't need external ram. You can choose a microcontroller w/ enough ram and you can avoid external bus. For your flash needs maybe you can get a serial flash like a SD card, cheap & easy.
Regarding retro game console, look for uzebox project, it seems exactly what you described.
It's my small contribution.
Cheers,
Celso