By now, you probably realise that I just love WSPR. With quite simple equipment it is possible to be decoded across the planet consistently with real QRP power levels. I am always on the look-out for new ideas, although until my health improves I am not in a position to build too much myself. See http://www.knology.net/~gmarcus/WSPR/wspr_v4.pdf for an example of a complete 30m WSPR transceiver.
This is NOT a new circuit – it has been around for some years – and it still needs a PC for the WSPR software. Some TX-only WSPR beacons use microprocessors to generate the WSPR TX messages, thereby freeing up the PC and consuming little power overall. Some sync to GPS to avoid timing issues too.