It might be nice to be able to tweak the player colors after a board is live.  I can kinda see why this is turned off but I can also see how the ability to manipulate the colors might be helpful.

This has been discussed before. Tom has mentioned that for whatever reason(s) it would involve too much re-coding. However, I believe you can change it when you updated your board version. I'd wait a few weeks just in case there are a few other 'minor' changes you want to make ..then kill a few birds..

Edit: Also it looks like you can do it within scenarios.

What M57 said, there were problems if games were in the Join stage and Player colors changed (and player colors never affect current games, ie Dev games). So they must be updated with a Version update and all future started games will see the changes.

Yep that's right - any games in the game join phase get broken if the color codes change. It's probably not the greatest piece of coding I admit.

How many shades of Black can I get?

Uh, 255?

256 if you count white (which if you're already counting 254/254/254 doesn't seem like too much of a stretch). Way more if you allow uneven scaling.