if you're somewhat passable with a dremel (and optionally, magnetic tape), you could just repurpose one of the 3.5" front IO extenders that are floating around the computer hardware shops or amazon. Its my plans for the S400, because I already got said front io extender, which currently is sitting outside of the
current case, hold in place with two long strips of magnetic tape.
I'm going to cut a third slot for the PCB / USB socket, next remove it from its original casing, and then attach it to the place where the original USB-A + USB-C was located, instantly giving me a) a 3.2 USB-C and 2x 3.1 USB-A.
So, you just have to find yourself a nice APU case, that has a bit space left where the original IO front PCB is located, and then add yours (if you're lucky, you only need one additional cut-out).
cu, w0lf.