If you need rubber parts and you can make a simple mold, you can make
your own parts.  Just get a small kit of RTV [Room Temperature
Vulcanizing] materials, mix, and pour it into the mold.  The next day
you pop out the part and do another.

If you're in a hurry, you can use dental materials.  They set up in
about 5 to 10 minutes (otherwise you'd have to sit in the dentist's
chair all night for a tooth mold to set up).  It comes in various
durometers from hard rubber to rather squishy.

I made mounts for a Violano key frame many years ago, and they are still
very good.  I don't know about making it any specific color.  I do know
that the dental material is sort of costly, but the RTV is cheap.

Regards,
Craig Smith
near Rochester, NY