NookDevs don't condone the use of 3G for web browsing or the like. I'm pretty sure its because they didn't want B&N to get cranky at them and ban softrooting full stop or something. Either way, don't expect something like that anytime soon.
However, I do believe that if you use a 3G sim card other than the B&N one, its unrestricted. More about that here:
http://nookdevs.com/What_we_know#3G