Thank, guys. Will report back if I hit paydirt.

So far I can find Bourns in the right value but wrong size, or the right size but wrong value. Continuing to look.

It looks like GuitarElectronics may have 100K pots that may work. I put a call into them to check. Also inquired about the 1M pots. They don't list any on their website, but it's worth checking.

Mammoth has 1M and 100K audio minis listed on their website, but does not indicate shaft lengths...so I sent them an email.

Will report back with what I learn. Thanks for the leads!