QSettings a level beyond "Application" to store per-profile information

I am using QSettings to store a lot of data for the user. I would like to have profiles in the application however, such that the user can choose a different environment on startup. I know I can just do "beginGroup" on the QSettings, but that has two drawbacks:
1. on Linux the one file for setting start to get very large
2. I can't use the QSettings default constructor, all users must know the profile name

I was thinking that I could simply abuse the ApplicationName and append the profile to it. That however won't be ideal on windows as it won't create the desired registry hierarchy.

Is there some way I can easily do this?

Why not use xml files?