I was originally talking about true programmability as in modifying the firmware to send different codes in hardware. I ordered the 109-key version and was toying with moving the tilde/backtick back up beside the 1. However, I'll be using it on linux so it's probably simpler to remap it in software.
I downloaded the SDK and it does indeed give you the opportunity to reflash the MCU via the USB cable. However, you'd need to reverse engineer how they've connected up the chip I/O pins. I suspect they probably haven't gone too far from the reference version included in the SDK. I wonder how hard it would be to dump the existing code and reverse-engineer it--it's written in assembly after all. I've asked TEK if they'll provide the stock firmware in binary form as a fallback in case someone screws it up, haven't heard back yet.
Also, I contacted Megawin about their evaluation stick in case anyone wants to test stuff out on something other than their keyboard. They said to go
here and quoted me $40 USD including shipping to Canada.