Well I picked one of the indoor tomatoes today...
...nice size, obviously a cherry tomato of some sort (this was a volunteer plant that came up in a houseplant pot, so I was never sure the exact variety).
The taste? Good! It was a tad on the firm side, so perhaps it could have had more ripening time-but good flavor (especially considering it had no direct sun!)
So the results are in: Can you grow a tomato in a south-facing window with white-sheet-filtered light? Yes! Will the tomato bear fruit if you hand-pollinate using a cosmetic brush? Yes! Will the tomato you get taste as good or better than anything you get in a grocery store? Absolutely yes!