I think Audacity would do just the trick. It would simply be a case of splitting each version of the song around 3:10 then mix & matching each part together. My two CD's are still at my parents (as are ALL of my CD's as it happens) so I couldn't do a high quality one right now.

EDIT: Just had a quick mess around with the mp3 versions I have of each version with Audacity and while they appear to match length-wise, the beats don't match up throughout the whole song. Clearly each version' s play-speed differs ever so slightly. I shifted the Alt. Version forward a little and managed to match it up so it plays seamlessly! Once I get my CD versions I'll try it with the wav files.