I thought I would update this slightly.
The Dynasty transmitter/receiver worked fine (once I stopped using it for the subwoofer), but I ended up with two subs and really wanted them toward the back of the room not the front. That would need two more receive/transmitters (SVS makes them) and I decided to try the alternative.
I ordered a cheap area rug from Amazon, and a thick-ish carpet pad, and made myself some wire guides for two coax and two speaker cables.
I sliced the pad up so that the wire ran in in a cut-out, with the little spikes holding the pad in place up against the guides.
With the rug on top the wires are not visible, and with even soft shoes you cannot feel it (though barefoot you can). It's not a high traffic area, so I hope this is protected enough, time will tell. If these get damaged I'll replace them and put a separate carpet pad on top under the rug. Or get a better rug (you don't get much for $250, but 'real' rugs, like good quality oriental, are thousands). I looked at remnants which are somewhat cheap (but require edging) but they tend to have pretty abrasive backs, at least the ones I found. Wouldn't hurt the pad, but might wear more on the wire.
So with this (once I get all the furniture put back) I'll have everything wired. Probably should have done this before, but decades of experience in industrial wiring just screams at me for putting wire under carpet.
Yes, I saw the flat wire, but wanted coax for the subs (neither sub nor AVR did balanced so that would have been yet more gadgets to set up). I figure this is good for a few years, by then I'll be tired of that carpet anyway.
Love those 3D printers. Note sure I could get them this flat and straight with just tape.
