I was lucky with my Nova, I bought it as a combo with a bird barrel and cantilever slug barrel for $400 brand new off the popular gun auction site (Got real lucky on that one). Rifled barrels for the SBE II are hard to find, cost north of $600 just for the barrel, and I don't believe are even available in cantilever. Much as I'm sure you love the SBE II, I would echo the above and keep that as your bird gun and spend the money on a dedicated deer gun.
Heck, for the cost of the barrel, you can get one of these bad boys:
http://www.remington.com/products/fi...cantilever.asp
Or, an H&R ultra slug hunter, hard to go wrong there. Or a....