Rather than PM this, I thought I'd post it here in case anyone else wanted to give a thumbs-up/thumbs-down to any of these ideas.
Interviews with . . .
Richard C. Hacker, author of the highly influential 1980s book The Ultimate Pipe Book
William Serad, prolific pipe-tobacco reviewer and blender
The owners of McCranie's, about whom I've heard very little (maybe focusing on their dated Virginia releases)
The managers of some of the country's outstanding pipe shops: the original Tinder Box (Santa Monica, CA), UPTown's Smoke Shop (Nashville, TN), Iwan Ries (Chicago), Jon's Pipe Shop (a personal favorite of mine, Champaign, IL), Barclay-Rex (New York City), etc.
A series on "How to Taste" (maybe with Brian alone, maybe with guests) that could focus on a particular style of tobacco each week, highlighting several blends that exemplify that style (English, Balkan, Scottish, Virginia Flake, VA/burley flake, etc.) and walking pipe smokers through the best way to discover everything a particular blend or style has to offer. This could also focus on particular types of tobaccos, highlighting several blends, say, that really showcase certain oriental flavors or that help you discern the differences between Red Virginias and other varieties. . .
A 2-3-minute segment called "Cellar or Smoke?" that takes a really quick look at a couple of different blends each week and offers a reviewer's opinion on whether these are blends to enjoy now or blends that are likely to improve with age. (Because, frankly, not everything is better with age.) Maybe it would also include a review of an aged blend that listeners might have rattling around in their cellars, discussing whether it's reaching (or has reached) its peak or whether it will likely improve with further aging.
Just a few thoughts. . .