Ok, nobody is interested enough to actually implement this.

I did a small amount of work and then determined 128x32 wasn't big enough to represent any data I cared about.
Technically the route display in gpsapp already draws 2 lines out of such a vector dataset, the route we're following and the track that we've driven. A scrolling image doesn't help in either of these two areas and as such is not interesting in my opinion.
After determining what I was going to be able to see, I came to the same conclusion.