Shop bike?

At car shops that customize you can generally count on finding one thing: the shop truck. It might be a rolling showpiece or something that has had just a few modifications done to it. It is a truck that is used by the shop for special runs to the store and sometimes shows off the work they can do, or even forever be a work in progress until it gets replaced by a newer truck. I want to create something like that, but since my budget doesn't allow for a car, I am going with something more my size: a bicycle. I am stripping apart an old school 10 speed schwinn mountain bike, and I plan to re-use some of the parts to keep cost down, and spray paint it flat black primer. Basically make it into something that will be for short trips to the store, but still be somewhat pleasant to look at, and look like it is not finished when it actually is. I am still stripping the frame down, if I like what I see this project may be a go.