It's cheesy and ugly, but it works. I've added some options to obdgpslogger to make it work with a UI.
It's here: http://www.youtube.com/watch?v=yXyaUuZWKA8
This is totally a "first version", I just wanted to show everyone that finally there's an open-source GUI that works on Linux and OSX to show the little dials everyone on windows has had for so long :-)
It's in SVN, for anyone interested :-)