ultra small leak in tubeless

[vqdriver]

i've got a slow leak somewhere on my 29er tubeless tire. i've been on tubeless for a while now and i feel comfortable working with them, but this leak is very slow and very persistent. i'm losing pressure over the course of a weekend and wherever it is, it's not enough to produce bubbles in ye old dunk test. i suspect the leak is too small to push sealant out the hole. i've tried reseating and replacing the valve core, laying the wheel on either side over night in case of a sidewall leak, and removing/reseating the tire in case of a bead leak. no go

any other ideas?