After temporary removal of the Knoppix-related files, and defragmenting twice, the main NTFS volume's minimal size is 308 GB - that is, 31 GB used and 277 GB free.

Impossible to shrink it more, according to Windows.

I was able to free up 282 GB, so there is not that much hassle to run Linux several ways on this computer now. BUT: Imagine I had wanted to use the disk for, say, NTFS databases, or video footage, but keep them apart from the program installs. In that case, my dear friends, Windows 7 wastes away half the whole disk, by insisting on the principle that a 10% filled disk volume cannot be shrunk.

So, effectively, I would have had to wipe it all clean and reinstall Win7, drivers and all..

Think I'm going to create that store.img image file 2-3 times as big, so that I can at least use that real estate for something useful...