[toybuilder]

A lot of folks are missing OP's point about making wearable tech. Flex in the US is just not fast or affordable. There's no reason for it to be (from the fabricator's standpoint).

OTOH, most of the stuff can be and should be prototyped on standard rigid boards.

For standard 2L rigid boards:

If you work in 1-week cycles, you can usually send a PCB out on Thursday or Friday and have it in your hand on Monday or Tuesday to assemble and test. About $40-$100 per round.

If that's not fast enough, a domestic fab shop that can do 1 day turn on bare boards for not terrible pricing - about $150-$200 per round (unless you can will-call at the dock). 2 or 3 day with soldermask/silkscreen will probably be around $300-$500 per round.

Prices are rough estimates off the top of my memory from the shops I've used.