I'm storing away cash to buy a Powertap in the near future and need wheel recommendations for it.

I ride 650's and have a set of Zipp 404's already. I was considering building up a PT wheel with the lightest rim and spokes I could and also making up a disc cover for it to use in appropriate races. Since it's 650, the CH Aero cover isn't an option.

Anybody have opinions on this idea and recommendations on which rim and spokes to use?