Unfortunately their are no other colors to be had, unless you have some suggestions. And then they would have to be realized only in strings otherwise it's not a string piece. Haha! I have never seen a ruby and wished it was an emerald. But I will say that there are real limitations to sampled strings and I would give anything to have this played with period instruments. I played a Handel Concerto note for note with these instruments and viola! It didn't sound that good!
But if you want to offer some back seat driving (I do it all the time) I would be happy to hear it.