If spondoolies was ever going to do something now would be the time.
Makes you wonder whether they were spooked by the same competitor that bitmain were worried about ... but were they, like bitmain, brave enough to place firm orders to have their chips fabricated?
More likely they didn't want to invest further in manufacturing current-gen technology whose bottom-end efficiency is pretty much on par with current or upcoming competition's stock efficiency, so they could put money into R&D for the next-gen stuff to actually compete directly with whoever Bitmain's worried about in another month or two.
Additionally, when factoring longevity into S5 calculations recall that BM1384 chips are rated to run around 0.25W/GH with sufficient undervolt/underclock. That takes the S5 from a 600W 1100GH machine to a 125W 500GH machine.
Did you ever get further into your project to make a DC/DC supply for the S5? I haven't updated the firmware on mine since I got it to see if the issues with running at reduced volts was a firmware limit, but I'd be interested to know if anyone's actually gotten them down to 9V stable.