Maybe I'm looking for a unicorn but do you guys know of any 27.5 XS boost hardtail frame from a reliable brand? It's for my 5'10" 4'10" daughter and I can get cheap boost wheels, hence this requirement. It seems that most frames I find are non-boost.

5'10" on an XS frame, really?

My bad, I meant 4' 10".

Did you find anything?  I am looking for the same because I have a 27.5" wheelset with boost on the rear.

Did you think about getting a 29" frame and just putting the 27.5 wheels on it with some big tires?  Lots of choices with boost 29ers.

Lloyd

What do you consider XS?

Just found this but have no idea of quality. Also note it is 650b + and has limitations re groupsets. Also BB drop is huge at 61mm  https://www.aliexpress.com/item/4000287778605.html?spm=a2g0o.productlist.0.0.1d032f82SMxMKK&algo_pvid=80b9f9dc-b68e-4a7c-88e8-acd750e5c26d&algo_expid=80b9f9dc-b68e-4a7c-88e8-acd750e5c26d-1&btsid=0be3764515826967715615198e9e68&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

It's the first mountain bike for my daughter and in the end I decided to buy a relatively cheap entry mountain bike. It's gonna be heavy but I can buy something better if she likes mtb next year. I'll convert the cheap bike to 1x and also upgrade the boat anchor fork with a used reba.