I got the idea to decorate my frame after seeing a guy's bike that he had covered entirely in black reflective tape. The black reflects white, and obviously isn't quite as bright as white would be, but when you cover a surface with it it still lights up. And in regular lighting it looked really cool - somewhere between a pearl and a metal flake and a carbon finish.

We have a friend whose winter bike has a crate on the back that is covered entirely with bright white high-gain reflective tape. In sunlight, it is fairly blinding to ride behind him, actually.