Keep ALL inside (and outside) window trim the same. White ALWAYS works. And white works for interior doors, base boards, crown and other moldings to set off paint colors. Those can be different.........: ) In other words, I'd stick to white.

I could easily be accused of being boring (on multiple levels), but I would stay with a single color as well.

Is it thermally broken?

I would imagine most exterior aluminum capping can be done in many colors?

i know they probably cant be a perfect match to a window with an exterior color other than white but can it be close?