RFX Teensy 3.x development board with Arduino shield breakout, prototyping area and nRF24L01+ headers.
This Uno-sized (7cmx5cm) carrier board for PJRC Teensy 3.0/3.1 is a convenient way to add nRF24L01+ module and Arduino shield compatibility to a Teensy 3.x project, as well as providing a general breakout board with prototyping area.
Note: The new Teensy 3.1 boards have 5V tolerant digital IO pins, making Arduino shield compatibility even more straightforward. (Note also that OSH Park have got a killer deal on the Teensy 3.1 at the moment -- all with PJRC's official blessing.)
Team these guys up with the RFXduino nRF24<->TCP/IP gateway and software, and you get a WiFi connected Due-class board for a fraction of the price of, well, a Due and WiFi card! (With greater functionality, too, e.g., access to https servers.)
Available as bare PCB, kit, or assembled. All through-hole components for an easy soldering kit.
http://embeddedcoolness.com/shop/rfx-teensy3-x-nrf24l01-carrier-board-w-prototyping-area-kit/