The front top tube is 57cm and the front stem is 120mm, which makes it about 2cm too long for me, and finding a replacement stem for the oversize fork will be a hassle.
We also have an older T200, and what you need is a Nitto threadless stem - quill adapter, which will let you use any normal 1-1/8" (28.6mm) threadless stem. I think what I bought was the SM1143. I pasted several links below, you might be able to find a supplier closer to you.
http://www.niagaracycle.com/product_...ucts_id=420644
http://www.amazon.com/Nitto-MT-Colum.../dp/B001LXM5W6
http://jail.sine.com/sheldonbrown/sh...1-4-quill.html
The 1-1/4" fork takes a stem with a 1-1/8" (28.6mm) quill, so the stem column is actually straight. A more "normal" stem column is for putting 28.6 threadless on a 1" threaded steerer, where the quill would be 22.2. Those columns have a step in the diameter to go from the 22.2 to the 28.6. But for the T200, the one you need is the same diameter along its whole length at 28.6.
Once you get it set up, it's actually really convenient if you want to quickly swap stems (say for someone else to try captaining your tandem), because the removing the stem doesn't alter the headset adjustment since the headset is threaded.
Hope that helps!