"...haven’t had a mo to check the normal sources, but if any ace researcher has a chance please feel free"

Maverick!
I think I've heard " She can't _____ for toffee" here in the Alabama south.
But we have a lot "can't for" phrases down here so I can't be for certain.
But what good luck.
Today I have a road trip planned to rural Alabama.
Can I be your Ace Reasearcher in the whole southern South?

I will report back to headquarters this evening.

- themilum, A.R.