What's a less profane alternative to "as f**k"?
Solution 1:
I'm XXX as all get out is common. Websters:
the utmost conceivable degree —used in comparisons to suggest something superlative
See also this stack question: Origin of “as all get out” meaning “to the utmost degree”
Solution 2:
The term "drunk as fuck", as you mentioned, uses "as fuck" as an intensifier — in this case a particularly vulgar one.
You mentioned you wanted a phrase. The phrase "as fuck" mimics a simile, using "fuck" as a word representing a generic, intense object. If you want a less profane term, you could invent a simile of your own. Here are a few examples to give you some ideas, with varying levels of appropriateness:
I'm as drunk as a Russian at a strip club.
I'm as drunk as a frat boy during initiation.
I'm exactly as think as you drunk I am.
I'm as drunk as Quagmire from Family Guy in a Never Have I Ever game.
I'm as drunk as a wood spider that had rubbing alcohol swabbed on its back.
It's a fun exercise in general. Try coming up with a few of your own.
Solution 3:
...as hell might work and be slightly less NC17
Solution 4:
A one-size-fits-all simile is "as can be", meaning "to as great an extent as is possible."
I'm as drunk as can be (although in my opinion, you shouldn't be able to speak at that point).
I'm as full as can be
She's as cute as can be