Stig: with RTW, I did a dual install just by installing, patching to 1.2 only, and using windows explorer to copy the entire RTW directory. I then patched the copy further, not the original. However, it is a fairly long process and takes a lot of space. I don't think I will bother doing it again. I will just uninstall/reinstall M2TW if Elberhard gets a battle; I have not seriously got into Kingdoms (too busy with Bioshock). I guess people with Kingdoms who don't want to do a dual install or a reinstall will have to be regarded as being off active duty until the next Diet.
Won't work for MTW2

I backed up MTW2 during 1.2 (working on a mod with some other guys). And those files are stored in the folder Backup, I can easely run that as a modfolder. Simply make a batfile and cfg file saying that it should start up from the folder Backup, but it still shows the version as 1.3

So it's either:
We patch for free (note: this patch does NOT change gameplay in anyway, so we wouldn't have to wait till a Diet Session).
Or about 5 of us won't be able to use something they payed 30 euro's for.