Of the frames I’ve owned the Adamant A1, Yaabaa 1499 and Atomz Quark 2 are worth a mention for what you’re looking for. Yaabaa was the shortest and most flexing rear end but took a beating. Adamant was middle of the two in terms of stiffness and erm… length but that thing took an absolute battering over the 4-5 years I had it so definitely the strongest and it rode very well. Over all though I’d say the Atomz topped them both, with a good set of features like the through axle, chain tensioner and construction with the stiffest rear end and it rode beautiful and looked beautiful. I got it second hand off of somebody on here, then rode it for a few years before selling it to Kyle Livesey who broke it because he is rough as 🤣If you can get one that hasn’t been abused I’d say go with that as it was a joy to own. Failing any of those a 2006 Echo control would be a good choice although it’s more like 1085 WB. Stiff as, does everything pretty well and absolutely flies up taps. One of those with a long and high stem could work as it certainly did for Bigman for a long time. Only trouble is the hassle of hanger brackets and having to make a tensioner.
Here are some vids with said equipment.