Retro Duo RGB mod?

[eastbayarb]

Has anyone RGB modded a Retro Duo before? I understand that even if there is, it probably wouldn't apply to NES, but I am more interested in SNES RGB on this thing (yes I know, a regular SNES has RGB, but I wanted the Retro Duo mainly because there is a black version).

Anyone know if backup units work on a Retro Duo like a Super Wildcard DX2 or Game Doctor SF7?