The one I have seen have the batting and backing sewn to the top and then just turned inside out and then quilted. (Sorry I don't know how to explain it better, I think some people call it birthing a quilt) I haven't seen one with binding, but I suppose you could do it, there are some great tutorial on the web if you search for binding odd angles
http://www.quilt-video.com/2010/02/0...ng-odd-angles/