That's a cool idea, Beaky....

However, if you make a registration (or UPG) for each style, rather than calling it up from the style section, if you then go from that style off to a different one using the same registration, you can always 'undo' simply by hitting the registration button again, thus reloading the style.

This will only work for one style change at a time, you can't go A>B>C>B styles, just A>B>C>A, but it's still better than nothing!