Yeah, I would be inclined to make my own. You could get an inexpensive project box, some good quality RCA jacks and some switches and put it together pretty easily. Good rotary switches are a bit tricky to find. There is either something like the Lorlin switches we use, which are honestly not quite as reliable as I wish but decent and very reasonably priced, or very expensive stuff like Goldpoint and Electroswitch. Not much available in between.
We fabbed up a box that matches our stuff using a 6" x 10" aluminum plate that I got cut at a sheet metal shop for $2, and one of our Seduction/Crack size wood bases. It just has RCA inputs, RCA outputs and the selector switch on top, and right now it feeds a prototype preamp that has a single pair of inputs like the S.E.X. kit. Bigger than it needs to be but matches the look and works just fine.