Zombie thread, but I'll comment anyway... I think it can work, but try to exercise some taste. I'm pretty happy with how a threadless stem and adapter looks on the PX10 I'm currently rebuilding. I do think you have to go with silver though, or matching paint. Black with white logos/graphics is never going to work aesthetically, for me at least.
Also, let's not forget Alex Singer and probably others were using threadless stems decades ago.

Sorry for the bad phone pic, but you get the idea.