I've found these:
https://www.tindie.com/products/Ba0sh1/esp8266-esp-0712-full-io-breadboard-adapter/
Not quite as nice as the Adafruit - no level shifting in particular - but worth a try until the Adafruit part comes into stock. Do you have a plan for the level shifting on your board?
Whoa - all the control is by the ESP? That's incredible! Too bad they are (temporarily) sold out of the Huzzah - it looks much nicer to work with than the bare-bones ESP.