Meaning: as in, if the sun don’t shine tomorrow I’ll eat my hat
Rewrite 1: eat my socks
Rewrite 2: eat the mower
Rewrite 3: eat the potato peelings
Rewrite 4: wear Dad's toupé

Comment: I tried to vary the last one so it shows the same sense of confidence that it won’t happen and the absurdity of the event if it does.

Check out the searchable alphabetical list of my cliché rewrites with the archive list at the right.