5’10.5″ on a medium Spitfire with a 50mm stem. I’d be surprised if you need a large.
I know there’s quite a trend for running very short stems, they’re not so popular amongst the quickest racers – I think once you go below 50mm you can run into a situation where the hands end up level with or behind the steerer tube, so effectively zero stem length and that means you get no stabilising effect from weighting the bars. There’s some interesting setup articles about Voullioz and Ritchie Rude’s enduro bikes that cover this.
The Banshees all feel shorter when sitting because the seat angles are steep but that makes them good at going uphill.
Philfive, normally a bike that’s too small will mean you end up going further off the back on steep descents, it’s on oversized bikes that you’ll end up stuck too far forwards.