Let's say I was writing a mod. Hypothetically speaking, of course. Let's say this mod involved a skill that lets you pass out drunk on the ground, triggering a spell that automatically reset all monster aggro to 0 and buffed you so they don't notice your presence as long as you remain stationary. How much stealth do you have to have to avoid drawing aggro from a creature right next to you? 100? More? Is it more convincing if you smell like Dwarven Rot Gut or Absinthe? Consider these questions to be entirely rhetorical. Except you should answer them. Please?
I'm not sure how much sneakiness you would need but I see no downside to putting it to 100 either way if you're not supposed to get aggroed.
I've messed around with adding large amounts to stealth and it appears that if a creature that has already been aggroed is adjacent to you when activating the ability, no amount of sneak is going to keep it from attacking you still. Then again, I may have done something wrong and could be mistaken.
The idea is to use a spell to reset make monsters passive first, then rely on the stealth bonus to make you invisible.
I think Essence did something on those lines for Ninpo in the old version of ES DOD II, and there was a crashing issue. You might want to check out with him.
Actually, right now, Ninjitsu level 4 (IIRC) makes all enemies within 3 square passive and turns you invisible. Works like a charm except when a monster resists the pacifying effect. going to +100 stealth in a breakuponmove buff is another perfectly excellent way to do it, provided it doesn't give you leave to bomb enemies from afar with ranged attacks without getting their attention. Pretty sure that wouldn't happen though.
I'm pretty sure they'd reaggro to you if you attack them directly. Wouldn't they? Have to test that...