There is a new unfired Stainless 30-06 barrel in the classifieds @Savageshooters right now for I think $100 shipped.
Yes, the 06 and the 270 are interchangeable. The good thing about having a long action is you can use almost any cartridge(long and short) in it.
You could also look into the Adams&Bennett barrels that MidwayUSA sells. They are decent barrels. As good or better than factory anyway.
The 30-06 is a better option IMO also. Alot more bullet selection than the 270.