I was was considering an old santana but ended up with a newer burley, so I won't be doing this upgrade. (I kind of wish I had an old Santana to fix up now, just for fun.) I measured my pine mountain (new 27.5+ mountain bike) and the spacing is indeed 141mm.
There are a few bikes that have gone to this hub recently--most commonly the Trek Roscoe. People are really hating on it because they consider it yet another hub standard. But as far as I can tell, most TA boost hubs (148mm) should be ok for conversion to 141 QR. This is explicitly the case for the higher end Hope, Chris King, DT Swiss, etc. They sell end cap conversion kits.
If you want something less expensive I'm sure they are out there. The hub on my pine mountain isn't anything special. But I've had a hard time finding them. I have a feeling that you could convert pretty much any TA boost hub, but I don't have any to play with.