Don't know what his intentions are, regarding sales. It's all open, though.
I find the 8 GPIO lines interesting. He mentioned they might be used to emulate a fast loader, I believe. But they could serve any purpose....  He's added this as a project listing at www.avrfreaks.net
I'm helping out with testing these things and I've already received an order of 10 of these. I just had to do it, so I decided to be the first person in the world with a working USB port for their 1541. ;D
Last night I finished the first portion of the mod which was to remove the IEC ports from a 1541 and solder in leads from the XU1541 to the 1541's motherboard. The heart transplant was a success and I'm able to use the drive just fine using the newly transported IEC ports (now located on the XU1541 board). I'm waiting for some time to set up a build system for compiling the OpenCBM sources from CVS so I can start testing the USB connectivity. THe great thing about modding the 1541 this way is I only have to add one more hole to the 1541 case for the USB port.
Eventually I'm going to rewire the IEC port wires with higher quality stranded wire to make installation easier. I'm also going to write up the parallel interface to the 1541 motherboard so I'll be able to use mnib with this drive using only a USB cable! The parallel connection may actually be the most compelling reason to install the XU1541 into a 1541.
I'm going out of town tomorrow and won't be back until Sunday, so pictures and a complete write-up will probably not be available until next week.
I'm also going to write up the parallel interface to the 1541 motherboard so I'll be able to use mnib with this drive using only a USB cable! The parallel connection may actually be the most compelling reason to install the XU1541 into a 1541.
Till just reminded me that there's not enough RAM on the xu1541 to store a complete track of data so mnib won't be usable from the xu1541. That's what I get for reading too fast and sleeping too little! However, I think the parallel connection is still very valuable as OpenCBM can use it to speed up transfers.