I just wrote up a new tutorial for turning prefolds into fitteds without using a serger, if anyone is interested. Just follow the link below.
I came across a couple posts wondering about doing this and I was looking to do it too. I spent a lot of time trying all the other tutorials and eventually coming up with this design, I'm really happy with the results and I really like how trim it is! Here's some pics:
Hopefully someone finds it useful.