I've blown this one up to poster size. Lines are pixellated but not too bad. I'm sure someone could render something from it to make it work.
I've got other images that I got from deermagnet (including the negative of this one). Lemme know if you're interested in them. I think I included them on the maintenance DVD but can't remember for sure.
I could try some canned software to increase the size and smooth it to see if the rendered image is useable.