I would also like this a lot. I also think the UI would have to be
quite advanced. In most of the cases you I don't need this function
(and I wouldn't like any trace of it on the map). In some cases I
don't realize I needed the function until after I have left the origin
point.
My proposal would be to record everything and provide some very nice
gui to select timeframe for graphicaly displaying the history of traces.
Tibor