A couple of quick questions.

1. Let's say that I file an IFR flight plan, and I decide to take off VFR at a busy terminal area. My plan is to get my clearance in the air while navigating VFR. Is this possible?

I always get my clearance before I takeoff; at least I did while I was in flight school. Now, I rent aircraft every once in a while with my wife, and we like to go on trips to help me log some time. Renting is very expensive, and I would like to use my time wisely. I hate waiting at an airport under the class bravo shelf, waiting for my clearance.

Can I takeoff and fly visually, and at the same time, try to get an IFR clearance?