I know a lot of people have made scenarios based on the Wiz 1/2/3/5 layout ... Snafaru's website I think has the most details on that (as he has also done that, I believe).There is a link to his site from my main page, by following "Other Links".
As for Wiz 6 or 7, no scenario editor exists to my knowledge (yet ). Of course there is a great character/saved game editor for Wiz 7 (and Wiz 1).
Tools for your Wizardry(r) toolkit