Its abviously been a while since your original post, but I thought I should write as we are getting into Tandem racing, as well.
We are looking at getting a set of Corima 4-Spoke aero wheels for the tandem. We ride a Seven tandem with full Campy and 130mm axle spacing (for road bike compatibility). We looked all over for a set of wheels that are "tandem friendly" and found the Corima wheels:
www.corima.com
The "HM" 4-Spokes state that they are strong enough for track racing and for tandems. They also have a disc wheel available that is also tandem friendly - make sure you get the "C+" model, however.
Yes, they are as expensive as hell, but we're already into the tandem for several grand, so what's two more? Besides, if you're willing to commit to racing, you are, by default, committed to spending a few extra bucks to give yourself as much of a mechanical advantage as possible.
We have friends who ride a HED H3 tri-spoke as their front wheel, but resort to a 38-hole Mavic CXP-33 or Velocity Deep-V wheel for the rear.
Hope the racing is going (went) well.