One idea I had recently was to make a bare bones Pro Mini style board. Since 328's are in short supply at the moment and SM 168's are about £1.80, I was thinking MCU, crystal, reset button and a few caps, same footprint as Mini Pro but with ADC6 and ADC7 brought out as well. No regulator for minimum cost. Probably could be made for £5 ($8) or so I guess (more for a 328). Plausible??