As a future request, I would like to see the faders take on the track colors like Track Name Labels do.
Just add a check box in the REAPER Preferences as show in Image below.
so now when you color a track, your Fader will also color to matching the track.
Below is an sample of what it could look like.
both the Track and the Fader have only part of it's image set with transparency.
This should help in themeing, less work.
Robert