This may be of some use:
http://www.thingiverse.com/thing:8025
It is a set of boards to produce a working Flash and SRAM cartridge
that will work with the Subor TV computer.
I also have a cartridge programmer design for download, but it is an
earlier design and currently there is no firmware for it due to a HDD
failure. (Don't be like me. Remember to do regular backups, people.)
https://github.com/EverydayInventors/8b1bprog
The hardware for both works, but is VT02 8-bit One-Bus mode specific
(used in the Subor TV computer, but not the Victor or King Game
computers.) If you decide to build the one-bus programmer, don't
bother installing the optional I/O chip.
I don't know the health of VR Technology, the company that makes the
VT02 chipset, but their web page is falling apart so I'd not put much
faith in VT02 based TV computers being produced too far into the
future.