I am the man or at least I'm handy.
Following Monk's example, I tried using the broken key in the trunk lock, where the other half resides, and was able to open the trunk reliably.
After calling around, it became clear that I would, indeed, need a locksmith. They told me that I could either pay $200 to have them come out, get my car towed to them (about $100 or so and it is nose into my covered garage area) or I could remove the lock from the trunk. That would only cost me about $30 to have worked on..
So, I attempted to remove the lock from the trunk. Boy, it sure doesn't want to come out. There is this one little clip holding it in and that isn't going to be budged. In fact, it attacked me so now I have a nice metal gouge in my left index finger at the joint (and I'm left handed!). This sucks.
Closer examination of lock and environment around it displayed a small open area at the end of the lock when I removed part of the mechanism. Using pliers to hold the flap at the entrance to the lock open in one hand and using an eyeglass screwdriver in the other, I managed to push the fragment of the key out far enough to use the pliers to extract it. Now I have a single broken key...
R is coming to get me and I get to go get a new key. Shee-it.
You can ping this entry by using http://www.khephra.org/mt-tb.cgi/175 .