I have been looking at AutoTrace a bit. It is an open source bitmap to vector program. It inputs and outputs a variety of different formats. ILDA is not one of them but it would be fairly easy to add. I should also be able to add a GUI to it so that you can see the input and output files as well as tweak the various settings.
But, before I go to that trouble I would like to see if anyone knows how good or bad it is at actually tracing? It has a GUI for it already but it is not for Windows so I can't try it out. If there are any Linux users out there who would be willing to give it a while and see if it is worth messing with that would be helpful.