I'd personally use a PIC breadboard solution. You can either build one from scratch or get a kit that includes a PIC chip and basic I/O board (including
serial or USB and some multiline LCD, some other details, and the
software development tools). It should be fairly trivial to write an application that starts up and immediately just scans the
serial port, updates the data, and loops. In fact, you've spurred me to consider doing the same thing at some point. I'm up to my eyeballs in projects right now, but if you do this, ping me and maybe we can start a thread on it.