Thx, discutable idea imho.
Changing trophy colours - no go! Would be a spoiler.
Changing form - impractible. Would give programmers too much of a headache. Too much work, simply.
Marking the trophies with initials (S, CF, R etc.) - well, this would require a new seperate listing in the player's profile.
Now that I come to think about it, I'm against it. I'd vote for simplicitly and clarity here rather than for adding a new info feature of... well, of secondary importance, sorry. Just my 2 cents.