Looks like there's good news for riders that like to run 23 mm, high-pressure, light-weight, high-performance tires on their recumbents. The Ultremo ZX is currently available in 650c and 700c sizes (I have a ZX on my Musashi's 700c rear wheel) and in the future will be available in 406, 451, and 559 sizes. Kind of pricey, though. See: http://www.schwalbetires.com/bike_tires/racing_tires/ultremo_zx.
 
The total weight of my Musashi with me on it is about 172 pounds. I pressure the ZX to 120 psi and don't really experience that harsh a ride. I'm running a discontinued, 451 Schwalbe Stelvio tire pressured to 115 psi on the front.

Quote from Patti on Sep 22^nd, 2011, 9:21pm:

 
Duranos are the better tire for your trike, particularly for the tire-scrubbing front wheels, because they are more durable than the ZXs. I like the ZXs for my bikes, because they are fast rolling and have excellent grip when the bikes are laid over in high speed turns.

Quote from FlyingLaZBoy on Sep 23^rd, 2011, 7:40am:

 
That's just not fair. Guess I'll just have to stick with paying for the heart attack food and homemade root beer at the Dairy-ette on Ferguson Road.