Nice Bike
They appear to be Matrix Titanium - a Trek wheel - the same were on our T50 until a few weeks ago when the rear developed cracks on both sides that go all the way around.
I built up a new set of wheels with Wheelmaster 40h tandem hubs (sealed bearing

, 14mm diameter rear axle

), Wheelsmith spokes and Velocity Dyad rims. At the same time converted from 7 speed to 9 speed, replacing the Deore RD with a SRAM X.9 RD and X.0 twist grip (flat bars). The new wheels are significantly stiffer laterally, and noticeably lighter.
More here:
http://forums.bicycletutor.com/thread-2920-page-3.html
The T200 and T50 have the same frame.