While a novel idea, the thing that gets me about time building is how that person will be building the time. Burning holes in the traffic pattern and VFR cross country flights are not going to make one ready for a job as an airline pilot. I had a few students that wanted to try this back when I was a CFI, and I asked them what they thought they would get out of blowing all that money to build time. And the answer was limited to the fact that it would get them in the door at an airline.

When you earn your commercial certificate, with the exception of adding on ratings, you should not have to spend money to build valuble flight time. Instruct, fly checks, fly tours, traffic watch. Get out there in the real world, out of the comfort of your local airports practice area. File IFR, go flying when the weather sucks, land in a strong cross wind and scare the crap out of yourself a few times. These things help you learn and give you the experience to become a good airline pilot. Paying $80 grand to get a 717 type with 250 hours is not real world experience. Does it get you the job, sure. But if the first time you shoot an approach in the crud or have to park that thing in a wind gusting over 20 knots is in the cockpit of a commercial jet, you skipped a few steps.