29er HT that can take a 29 x 2.6 at the back, no steeper than 65deg HA, built for 140-150mm fork. Not fussed about material.

Canfield iirc have an offering which may meet those requirements.
Yelli Screamy .

You would’nt get a 2.6 in my Mk2 Yelli.Though not tried it ,there was masses of clearance on my Nukeproof Scout 290.

Not that I’ve tried a 2.6 but a Last Fastforward would swallow one with ease I would think.
64 degree head angle too.

You’d be surprised how few claim that wide will fit. Mainly because the trend seems to be dual wheel compatibility, so if you want wide, stick a small wheel in there. Not what I want, I want a 29 x 2.6 at the back. The new Orange P7 is ticking it at the moment, but they haven’t designed it for a longer travel fork. With such a low BB and a steeper HA, I guess a 140mm would work on it.