SharePoint 2007 Subsites with Different Templates Than Their Parent
Sometimes things are really simple but take some time to figure out. I was just going to write this up, but looks like someone beat me to it. Here is how you create a subsite with a different site template from its parent.
http://techblog.udayakumar.net/2007/12/how-to-create-subsites-with-different.html
