Dynamo Hub question
 

I want to get a generating front hub wheel for my Trek 7700 FX.
Do I buy the hub and get the rim relaced, or buy a whole wheel somewhere or what?

What's your source for the hub? Laceing a new rim onto a new dynamo hub doesn't sound to me like a particularly difficult problem. Any average-or-better bike shop will have somebody who can do it.

I don't have a source yet, I just know I want one.
Any help would be great

It's easier to put a new rim on an old hub than to put a new hub on an old rim. You would essentially have to have the whole wheel relaced, and would probably need different sized spokes, the flange on the dyno hub is a lot bigger than on most conventional hubs. It would be a good time to upgrade your rim, if you so desired. Peter White Cycles on the web sells a lot of dyno hubs, and they'll build the wheel for you.