I recently got one of these ZIF devevopment modules for 40-pin AVR,
mini-dev-board
I'd purely love something like that for 28-pin 328P breakout, but I don't need the power plug and regulator, just extra 5V and GND pins.
Could you sell both ZIF and matching socket versions populated and bare boards in multi-packs?
Sell the chips and a programmer, or integrate an ATtiny programmer into the ZIF board maybe?
And then you have the full hardware set for a Minty Boost Kit; buy this. do that......
and I will have my ZIF 328P dev board with standalone target boards available.