Actually, Progeny is based on Potato, with quite a bit of testing and a few new packages thrown in. Upgrading Progeny to KDE2.2 would be only slightly easier that upgrading Potato. I've had a look at what Progeny wants to upgrade to install KDE2.2 and I won't try it yet. I'm still waiting for the freeze to try KDE2.2.
If you are that adventurous to try KDE2.2 then just upgrade to woody now and give it a go. Lots of people on this list seem to like it. I'm just not that brave. Cheers, John Gay