No more need to manually download tracks you previously uploaded to openstreetmap.org first, then opening the downloaded file with JOSMs "Open file ..." dialog. You can now pick an uploaded track and have it loaded into a new GPX layer directly with the help of the DirectDownloadplugin.
You can download the compiled plugin .jar or the source code, but be warned: current status is "works for me" aka. "proof of concept".
The desired functionality is there, but it still is a bit rough around the edges.
The bigger picture about this plugin is that i'm tired of fetching track files from my Android phone more or less manually (either via USB or by SD-Card). So the plan is to remove all those intermediate file transfer steps by:
uploading tracks from within Osmtracker for Android to openstreetmap.org directly
then fetching tracks to work on from my openstreetmap.org track list directly from within JOSM
So step #2 of this plan has now been implemented, now its time to get my hands dirty on the Android side of things ...