Yes. There’s been several group buys over at the MidiBox.org site, but it looks like the current one (the 3rd) is pretty much closed as there aren’t any more GM5’s available from that source. It comes out pretty cheap for a very good 5x5 interface, but unless you have experience with electronics I don’t recommend it. The only hard part for me was soldering the damn chip in place; it’s so tiny, I ended up gluing it to the PC board so it would stop moving to allow me to solder it. And soldering these chips is a bit challenging: I ended up using the “flood and suck” method 
I’ve built two of these and they work perfectly and are natively recognized on both Mac OS X and Win7-64. But ploytec provides a good driver for windows which runs even better. Obviously I’m using these on W7. For less than 30 euro in parts each it was a good deal.