From the restoration project I linked to:
I was lucky to find that one of the Behr colors was a very close match: Behr Kumquat 230B-7
Are you planning on stripping off the black?
There are definitely better cabs to MAME for general-purpose use. At this point I'd definitely say it's worth it to get the cap kit done and get it to a working state as Super Mario Bros. IIRC, you'll have to hunt down at least a new wiring harness to convert it back to DK/Jr.
If you want to go the MAME route, You could make a new control panel so that it could always be converted back. For only classics, you could fit things into a Nintendo panel if you want:
Joy Button-button-button Trackball
2-player setups on a classic Nintendo cab are a tight squeeze. That's why they made the widebody cab for Mario Bros.
You might want to see what's invloved in converting it back to DK.
You can download the conversion kit manual for Mario Bros here. Do it in reverse to convert back to DK
I'm not sure if Vs Unisystem uses different wiring harness or power supply.