Hi Dawie,
Have you seen this?
Although it's not exactly the same there is an overlap - something happening in the background, while you get on with other data collection.
I would also find this feature useful for monitoring paths and trails.
At present I use a separate GPS app (GPS-logger) and then attach the GPX file to my form - those lovely folk at ODK have just implemented the 'file' widget to facilitate that! This means that all the data is in one form, collected on one phone - would that work for you?
As a new feature, I don't know enough of the mechanics, but for me it would be important to make sure that if the geotrace is running, it is still possible to collect other geopoints. So far with all the apps I've used there is always a conflict in trying to 'overlay' lines and points within the same data collection process.
But it would get my thumbs up too. The program flow seems logical.
All the best