Amazon is running a sale
right now on the 4 seasons of The Bob Newhart Show
that are already released on DVD. Each is currently going for $14.99 per season set, which is a nice price to fill in any holes in your collection. Also at that link is a pre-order listing for Newhart - The Complete 1st Season
, which ships in two weeks.
If sales pick up on the existing releases, then maybe it will convince Fox to release more of Bob. That's the only thing that they need to be convinced, is good sales on what's already out there, so get to it!