I would imagine as the Nook Color is becoming a full-on Android tablet, this will become lots easier.
For those of us that live on our Nook Classic (and soon-to-be hopefully-rooted-soon Nook Touch) options are going to be more limited.
I did just run across this brand-new thing: NookOPDS which is a python script that will do EXACTLY what I want:
I need to track down the two people in that thread to see how it works - I can't figure out where the python script plugs in... It looks to me like it can be hooked into NookLibrary... (?)