Sorry for the late update here -- I received the new boards last week and put together the new prototype! The delay is that I did have some trouble with the new boards as there were a couple errors in the layout, so all my spare time has gone toward working on it. I've now finally got it working, and have made the corresponding changes to the design. I'm testing all the fixes as I go (by physically making the changes to the hardware), so I can be more confident of the next boards fully working. Now that I've got the basic hardware working, I just need to finish porting the firmware to the new MCU (which so far is very nice!). The built-in USB interface works great, now that I figured how to get the boot loader working and all (that was another delay this week). Once I'm confident I've got all the bugs worked out of the hardware, I'll order the 25 prototype boards, which, if all is well, will be the ones shipping for the early prototype backers.
By Wednesday I should have the code ported and running, so I'll try to post another update with the results later this week.
What this means in terms of timing is that the prototype probably won't ship until the end of March, which is slightly behind schedule, but the final product is still on track. I've got a factory lined up for producing the final product and will be meeting with them next week to go over the details.
Thanks again for the support!