I guess I'll buy a larger SSD and clone the drive onto that before doing the upgrade then.

Do you know any way that I could move just the OS onto the SSD?

I have windows 7 on a 750GB drive at the moment, but I want to install 10 on my SSD which only has 30 GB of space. Of course, I don't want to have to re-install all my data. If I go the upgrade...