Trying to find 29er UST rim options for a custom XT dynamo front and Alfine rear hub build, but am struggling to find genuine UST rims. Before anyone suggests Stans rims, they are not UST.
Do they exist?
I haven't found any.
Lots of tubeless ready as you say such as DT, WTB, Stans etc. not found a UST like the Mavic 819 (but bigger). Only real option would be Crossmax or similar.
Don't forget there aren't many UST 29er tyres around so the full UST solution is hard to achieve.
The only officially UST badged 29er rims I know of are those that come in the Mavic Cro29max wheels. Perversely they are some of the worst rims I have used to set up tyres tubeless.
enve?
My Easton Haven rims are UST. Extra UK is the distributor for Easton products so you could drop them a mail to see if they keep rims in stock.
Shimano build 29er wheels with UST rims like the XT M785. I don’t know if you can buy the rim separately but an option might be to tear down the wheels and sell on the hubs. An expensive option admittedly.
You're correct that Stans aren't UST but the difference is slim... I run 2 sets of USTs and 2 sets of Stans and once taped up they're essentially the same. Very rarely you might damage the tape and have to retape but that's rare (I think I've done it twice now on all my Stans-ish rims, Rovals and Olympics and Flows and Flow Exes)
So personally, I would not be put off by UST-ness or lack of.