Jack, What you are talking about is a double boot (except for Wubi which is a special case). But there is nothing easier than running in virtual.
With double boot you have to bring e.g. Win7 down and then boot Zorin which is very inconvenient. Zorin is a full operating system and has to be treated like e.g. Windows 8.
Just think of your scenario with Windows 8 - would that work ??