@KitRedgrave @er1n You should still be able to get a PIC microcontrller which is a static design that can work from 20MHz all the way down to zero to "pause" them.
The 2600 system clock ran at colourburst/3 speed (for NTSC about 1.2MHz). With today's tech building something as simple as a 6507 and TIA is probably more accessible to hobbyists than ever before actually. I think it isn't done often because being creative in such an environment is extremely challenging. #racingthebeam