I think the good choices are 338-06, .35 Whelen, 9.3x57, and 9.3x62. Even though the 9.3x62 has gotten more press in the US in recent years, I don't think you would be giving up too much to go with the 9.3x57 with an 18" barrel like the OP has in mind. Don't know which would feed better in the 760. Either is a looney cartridge.
My father has a 35 Whelen Rem 760 as a bear gun in MT. I clearly see the utility of what the OP is trying to accomplish. Put a low powered straight tube scope or one of these new fangled red dot thingys on it, and you would have a slick rig.
