I am not aware of such a possibility - that would be handy for us as well - splitting out the SHARED files is not an issue for us, but the LOG files would be practical - but I don't know how. As far as I know, it's in the QlikView_code and cannot be changed easily.
You could use a macro or batch instead to parse the folder and move all the SHARED files into another folder prior to backing them up. Would that work?
Note that you could make use of the Shared file cleaning TOOL that is built into the QVS executable since a while. This tool lets you verify Shared file integrity & correctness and clean out whateve is corrupt. It may not solve your backup problem. But at least it will let you know without delay when something is definitely wrong with any of the shared files if run on a regular basis. It will be sufficient to restore the previous days backup, and you can keep your current 10-day backup strategy.
For more information, see the QlikView 11.20SR10 Release Notes, Chapter 16 (last one).