Here is a link to powerpc mags list of homescreen editors for wm5:

If the link doesn't work follow the path below:
http://www.pocketpcmag.com/_enc/encyclopedia.asp
Software > Utilities > Theme Creation/Management

This is a pretty thorough list since there are not very many WYSIWYG editors.

Please post additional programs that you have found.

At this time I am using Homescreen Designer WM5.0 from ruttensoft. I have been having troubles getting the alert pages to adjust.