Starting with the big picture: you can run good-quality studded tires (Nokian) on dry pavement. You don't have to take them off just because it isn't icy. Yeah, they're noisy, but they can take it. So if that was your reason for wanting a second set of wheels, it's not totally necessary.

Anyway, they're 700C and your local shop can buy off-the-shelf prebuilt wheels or custom-build some for you. For wintertime use, how about some of the economical 6-bolt Deore front and rear hubs, DT 14-gauge spokes, and WTB SpeedDisc rims. If those are carefully hand-built, they should be better than your original wheels. If it were me and I knew you were going to use them all winter, I'd open up the hubs and give them some extra grease too.

If you can afford to go up to the DeoreXT 6-bolt hubs, they've got better seals. Another upgrade would be using DT 14-15ga. butted spokes. Oh, and you'd want another pair of rotors and a second cassette.