First versions of Pro Trinket 3V Shield Schematics Are Here!
One shield is for the receiver hub (aka Gateway) and won't change too much except for exploring different terminal protocols for the Gateway (e.g. Direct to computer serial like thi one, vs WiFi, LoRa, and Bluetooth). Basically, only the header for the nRF24L01+ was needed.
The other shield is a general-purpose i2c (designed with the MPU6050 3-axis accel + 3-axis gyro in mind, but can take any i2C device) with 3 general purpose Analog inputs. A custom circuit on the Analog input lines enables a choice of either using a 2-wire voltage divider (variable resistor) sensor, or a 3-pin powered sensor (takes 3V, GND, and outputs analog signal). This is meant to serve a wide multitude of general sensing purposes, where one may also choose to not populate the analog or i2c headers if not being used. Also comes with a LiPo JST battery connector, power switch. Header for nRF24L01+ also required.