One thing to consider since this thread was started, is there is now the L23 routerboards:
https://mikrotik.com/product/l23ugsr_5haxd2haxd#fndtn-downloads
Now it is not USB 3.0 nor built in antennas, and you’d need a case… but does have same AX drivers without soldering or mucking with bootloader. Not saying the L23 solve everyone needs here (and I enumerate my complaints about the L23 here: http://forum.mikrotik.com/t/netmetal-ax-l23-ugsr-initial-feedback-from-specs/175780/1) — but it might fit some use cases for modifying an hAPax2 since it’s roughly same form factor.