Jag har för mig att
LVM hade något som liknade det du ville uppnå, jag vet dock inte om det funkar med Windows.
Edit:
"With LVM you can abstract your storage space and have "virtual partitions" which makes it easier to extend and shrink partitions (subject to the filesystem you use allowing this) and add/remove partitions without worrying about whether you have enough contiguous space on a particular disk, without getting caught up in the problems of fdisking a disk that is in use (and wondering whether the kernel is using the old or new partition table) and without having to move other partition out of the way", det låter ju som det du söker.