Any of those would work fine. I'd go w/ the trek 7.3 & the 700c wheels.
It's easy to find 1" 1.25" and 1.5" slicks for 26" wheels. I think those 26" wheeled bikes come w/ slicks, but you can order new ones from performance for about $8-10 per tire.
You might focus your research by calling local bike shops up to see what they stock. That way, it'll be convenient to try it out and pick it up. If there is a bianchi dealer...
http://www.bianchiusa.com/06_boardwalk.html