I caught an interesting instructable where user nurglets created a stacked macro filter of sorts. They basically purchased a damaged kit lens from an auction site, and removed the rear lens assembly. The lens assembly then was attached to an old filter making a half stacked lens macro filter gizmo. It is really an interesting build.

Here is a photo of the kit lens being pulled apart:

Here is a photo of the assembled contraption:

Here are a few impressive sample shots:

They did a great job on the build. Please check it out at:http://www.instructables.com/id/The_MacroGyver_or_home_brew_macro_filter/

I am curious what levels of magnification they are getting though and how it would have compared to just reversing the kit lens.