I know an East Coast Jamis rep who's been pitching this frame for months. All of my bikes are Jamis as you can probably guess
(it pays to have a hook-up
) and typically you get alot of bike with a Jamis, compared to some of the other smaller bike mfgr
To answer your second question, I can only speak for Shimano stuff, but yes the parts are interchangeable.
Now, if you ask Shimano that they'll say no. They'll argue that the tighter manufacturing tolerances on their upper end stuff, like Ultegra, wont integrate well with their lower end stuff, like Sora.
Thats Horse-sh*t. Shimano wants you to upgrade your entire drivetrain system in one shot
(Cha-ching
). And if your local LBS tells you the same thing, they are just trying to get into your pocket, and you have my permission to kick someone in the b*lls
(just kidding
).
Now that being said, if, for example, you have Sora shifters and you upgrade your rear dérailleur to an Ultegra, you probably will only notice a slight difference in the quality of shifting. If you were to upgrade both components, shifter and dérailleur in one shot, you'd probably see a bigger difference in shifting.
I've built plenty of Frankenstein bikes with stuff I have bought off Ebay, or just lying around, and its never been an issue.