What kind of features are you looking for? Chances are, something like it exists already but you just don't know about it. Custom clothing lines tend not to be very economical though if cost is no object, it should be a fun project.

Personally, I'm very happy with my Craft Thermal windproof fleece and Gill Prospeed waterproof jackets. Both are bright without being obnoxious, have plenty of relfective piping for foul weather cycling, and do their jobs admirably.