Using double sided assembly on FR4, an Atmel AT328P microcontroller module and an Anaren A2500R24A transceiver provide a small form factor platform for construction of a variety of wireless sensors. We've used the Analog Devices ADXL335 3-axis accelerometer to build a demonstration of a multi-channel analog sensor powered by a CR1025 battery with wireless connection to a computer display. The modules, radio, and battery also could be interconnected by use of a miniature ribbon cable, as suggested below.
Miniature wireless sensor modules connected by a flat cable with 0.025" conductor pitch.
Microcontroller, radio, and accelerometer modules on small FR4 board. Width of the board is about 10 mm.