At the moment I am level 47 and all the dungeons are filled with Master Vampires and tougher growd. If I level to 81, will the enemies also get exponentially tougher. Even with 100 one-handed and 100 block the enemies can withstand quite a good beating (without abusing alchemy, BS, enchanting), and if they get lot harder after level 60 or 70, I might have trouble killing them.

From what I have heard 50 is when the enemies stop scaling. From there on in you increase in power and they do not.