Really all you need is something with 135mm spacing that will take a 10-speed SRAM/Shimano cassette. It doesn't have to have disc brakes, and it really doesn't even have to be 700c since you won't be using the brake.

If you get a wheel without disc brakes (or at least without a rotor installed) you won't have to worry about the rotor lining up right in the brake slot.

As a bike commuter, I find that tires reach the point of flatting more often than I'm willing to deal with long before the tread is gone, so I use old commuting tires on the trainer. Since you won't be cornering or hitting bumps, the tire width (relative to the rim) is even less critical than usual (and the published charts are already conservative). If the tire will stay on the rim at the desired pressure, it's good enough for use on a trainer. That said, I would probably avoid really wide rims to match up with old road tires (or trainer-specific tires if you want to be pro).