[It wasn't... I can't do math. Embarrassed.
(My first "deal".. I hope it's worthy.)
Trying to find a way to add 10k to get to Gold, I found a r/t through PHX from PHL to PDX and then back for $504 ai. Same day turn.
Check my math - I think that's 12,320 miles, or 4CPM. With my 25% bonus that gets me to 3.2CPM, 15.4k miles.
Is this decent?
Edit - I was using the mileage calculator wrong, and adding the roundtrip in, so it was effectively doubling. How stupid.