You could alleviate the "I didn't get my fix" factor by not having the B sides interrupt the normal posting schedule when they are made public. With that you don't have the gap in new content.
On general content - I really liked the debriefs of Know Evil & New Arcadia. I realize that requires a campaign of some sort, however the concept was intriguing. I would also be interested in throwing cash at a "classics" setup i.e. playing a bunch of old established scenarios - Tomb of horrors, etc. A series around designing an actual system might be interesting - design choices, themes, etc.
As a simple business curiosity, I'd be interested in seeing if you could create a standing DM and / or player service. Basically, an RPPR member on retainer for a group via web games or a one time Blood Bowl-esque gaming merc. It always seems to be a popular selection in the kickstarters. Entertain my curiosities please.