Nice story, thanks for sharing mate.
I keep Windows XP on 4 GB FAT partition on the laptop just for 3G connection, but after I made it working on FreeBSD I never boot that Windows again, but I have a Windows XP virtual machine at VirtualBox for several apps that are 'so last century' or just their creators does not know what standards mean.
The backup plan for the 'real' Windows was quite simple, before install do
dd < /dev/zero > /dev/ada0s2 bs=8M, then install, then after all drivers installed, do
dd < /dev/ada0s2 bs=8M | xz > /backup/xp.xz, as for the virtual one, just
xz -c vbox_xp.vdi > vbox_xp.vdi.xz ...