Suppose you have a 3-vector called 'titleColor' that holds the RGB components of the color you want to assign to the title (which I will call 'titleString').
tStr = sprintf('\\color[rgb]{%f, %f, %f}%s', titleColor, titleString);
title(tStr);
I haven't tried this trick with labels yet, but I don't see why a similar approach would not work.
And yes, there are two backslashes before the color[rgb] in the code above. The sprintf command drops one of them.
