I have two working Pixelnet USB Dongles. Since I have upgraded to the Etherdongle I have no need for one of them (I'm keeping one for back up purposes).
You will need to reflash the firmware to make it a DMX Lynx USB dongle though (I believe it can be reflashed to support DMX, since I was using it as a PixelNet USB Dongle, or I can re-flash it before shipping)
Here's what I paid for it:
Pre-cut Case - $5
Parts - $46
PCB - $4
So the price would be $55 excluding shipping (I'm in Rocklin, California)
PM me if interested (but I've just noticed you are in the UK, that might or might not be an issue)