Last year, around this time of year, I had Waltly build me a custom TI 29er hardtail that was Super Boost based. (Fits 157 rear hubs.)
I purchased many of the parts for the build off of Aliexpress. But, I was not able to purchase any cost effective lightweight 157 rear hubs. I ended up purchasing XT super boost hubs via E-bay deals I found, and built up my own rear wheels. (Front wheel prebuilt and ordered spokes and additional carbon rims from CLANNAD.)
Since May this year, I road over 1000 miles on this particular bike, including 2 multi-day bikpacking trips. I really like how this bike turned out, and do like the super boost geometry, including the wider BSA 83BB shell on the frame.
The reason I am sharing this is that about a year ago, I contacted every seller of hubs on Aliexpress asking if they were going to sell a super boost version of their hubs. All of them said yes, but close to a year has passed, and few are listed and actually available.
I ended up working to some degree with a couple manufacturers of hubs via Alibaba. I can get a great price, for an under 250 gram rear hub, but I have to purchase a minimum of 50. (Tried the "sample" route, but they haven't wanted to let me purchase several samples.)
I figure, since super boost hasn't really taken off, Chinese manufacturers aren't willing to manufacture 157mm rear hubs on their own.
Similarly, I can't find a single super boost frame for sale on Aliexpress.