I've actually done a great deal of research here. It seems that BN just doesn't want to make it easy if you're not a mainstream magazine. IMO, I think some of it has to do with the fact that they aren't ready yet with a solution for app-based magazines. (i.e., Wired on the iPad.) This is likely because you can't yet author directly out of Adobe CS5.5 DPS like you can with iPad, Xoom, and even Playbook. From what I gather, there are some things in the works, but it's not ready for prime time.
From a consumer standpoint, the expectation for a "tablet magazine" seems to be that you'll have all of the wonderful interaction that examples like Wired have proven. Coolness like 3D content in ads and stories that you can spin around, high resolution imagery that you can pinch-zoom, rock-solid landscape/portrait layouts that are position-aware - all of these require the advanced (custom) interface that DPS will allow you to author.
From an independent publishing perspective, I've found a "way in" after really pushing BN (way too hard). While they have a large number (and growing) of mainstream magazines in the Nook Newsstand, it seems like they are very shy at working with non-mainstream magazines in general. They really need to be sold on the concept, the market, your editorial calendar, etc.
As you have likely seen, the Nook Newsstand mags today are all very similar in behavior to ePubs. With that said, I've found a way to really push the envelope on interactive content for what can be done today with the Nook Color. Some is still a work in progress, but it's looking great.
If you want more information, just send me a private message here and I'll discuss it further with you. I want to keep in good standing with the powers that be, so I don't want to post everything here.
Good luck. I hope we can all make a big difference on this platform.