Zonatandem:
I hear what you're saying and I appreciate the feedback. The problem is that there is no way for me to test ride the bike before I would have to buy it.

I was actually more concerned about the stoker frame size then the pilot frame size. The reason being that I've also been shopping a few Mountain bikes for myself to replace my 20 yr old Marukin Northstar. My old Marukin has a 21" frame size which is 2" shorter then my road bike size of 23". However, I've noticed that some of the newer mountain bikes have frame sizes that only range from 15" to 19". So, I'm guessing that mountain bikes have changed or sizing requirements have changed such that average sized people typically use smaller frame sizes that they use too. At least for moutain style bikes. I think the T900 is more of the off-road or at least a crossover style (rather then road style). So, I was figuring that the 18.5" pilot size would be adequate for me. Maybe, I'm making some wrong assumtions here???... not sure.

The other thing is that everything I read about the bike indicates that it is often used for an adult pilot/child stoker combination. Which is why I am so concerned about the stoker frame size being only 14.5". However, I must say that my stokers current road bike has a 19" frame and it is clearly much too large for her. So, I'm beginning to suspect that you are correct in saying that a 14'5" size might be a good fit... at least for this style of bike.