Ryan:
I'm aware of that issue, I've had it several times.
Turns out the problem is that the usb port has come loose, so badly that I couldn't get it to charge at all before. I fluked on getting it to charge this morning when I picked it up.
The guy in the store tells me that it looks like I damaged it, which makes sense since I dropped it on Friday and had to pop it closed. The next time I tried to charge it I had the problem. As Toby saw I was so sleep deprived I completely forgot. I'll check a bit later for myself.
A replacement 2012 model is on it's way, ETA tomorrow or the day after. If it's clear that it's a manufacturing fault I'll get a refund instead.