I have ordered a development kit for the nrf24le1 SoC. I have also begun porting the RF24 library to the 8051 processor with SDCC. If it all works out the whole board will be a tiny little thing. I have also been playing with the idea of expendable sensor boards that connect to each other through I2C.

On another note, if none of the SoC stuff works out, I found some very small nrf24l01 modules. 12x18mm I think, so about 25% of the boards in using now. I will be testing them sooner or later as well.