"Has Archive" needs to have string support

The “Has Archive” needs to have string support, as well as boolean, so you can give your single’s a different slug than the archive page. For example, a post type of “Attorneys” defaults to “http://site.com/attorneys” and “http://site.com/attorneys/john-doe” but what you might want is “http://site.com/attorneys” and “http://site.com/attorney/john-doe”.

You could just make it string supported in general since a blank field would result similar to boonlean of false, where as a filled field would result in boonlean of true, and you just default it to be the default slug.

http://wordpress.org/extend/plugins/custom-post-type-maker/