Oblivion's character leveling is different from Skyrim's. You level up by actually doing it, and you don't need perks. If you want to play as a sneaky mage, go sneak and throw fire. That simple.
I don't think you're gonna find any here. You might could try google. I've never used a pre-made build for oblivion because it's so free. Just go with what comes natural, man. The build will sort itself out it you're playing oblivion.