Here are some pictures of my small hardware hack.
First, I just added 3 header pin sockets to the already exposed debug port:
But that proved too cumbersome to maintain a good tethered connection to my laptop (plus the batteries would have to be exposed).
So, with the aid of a master machinist (Sandor -- a co-worker), I put a stereo "micro" jack on the top side of the device:
Here is the finished result:
You can see where I (badly) pried open the case ;-)
And here is where I am today:
Now, onto software...