I hope a chinese manufacturer makes one soon. The teardown for Echo had the parts for a bit more than that, but you could do it cheaper, multichannel ADC and half a dozen MEMS mics. I guess drivers would be the time consuming bit

The board actually doesn't appear to have an ADC, the microphones output pulse density encoded digital data wich can be directly received and interpreted by the processor.

I'm curious, how would you recommend they be priced?

Every comment that starts with "curious" seem to be spam on HN. Is this always the same guy or a bot? Almost every HN topic contains one of these "curious" comments...

It's a common English idiom, but even though I've been here over twice as long as your account date I can't say I've noticed an infestation of "curious" comments... though given curiosity is a hacker virtue, perhaps it's not surprising there may be more of it here? I still am genuinely curious how GGP would have dev boards priced instead -- the market is pretty much limited to students (the ones at good schools have the schools pay for the boards, or the schools get discounts) or professionals (who again expense through their company), what's the incentive to lower prices?