So you were sooo right Leo! o)
I searched the internet for some advice on how to add non-indexed network locations to a library, it really can be done by editing the "library-config"-file directly. It is not very userfriendly, I guess that's intented by microsoft, but I found tools to handle this, which then turns this into a piece of cake.
Watch this:
[code]>C:\SLUtil.exe create "MyNewLibrary"
C:\SLUtil.exe addfolder MyNewLibrary" \192.168.0.1\d$
[/code]
SLUtil.exe is part of a dual toolset I downloaded here: grimadmin.com/filemgmt/index.php?id=5
It should be quite easy then to select a bunch of folders, create a temporary library and adding the selected folders to it.
After that, flat view should be available for these kind of "FileCollection"s. Must still try if this really works out that easy though. o)