Just bought a new datalogger/GPS mouse. It's a nifty little thing which has 44 channels. It's very precise. I can use the IPAQ to connect to it over bluethooth, but it can also log on its own. 330000 points.

So from now on I'll have two independent gpx tracks to work with. If only I could find a way to set its clock. All the rest, I already achieved. BT access from the IPAQ and from the portable, translating the log output with GPSbabel and uploading it with josm.