Not a direct derivative, but similar to: http://www.thingiverse.com/thing:5551

I have found there are many times when I want to connect one piece of something to another. Having a generic trapezoidal key and slot system goes well for such applications.

This set of things provides a simple trapezoid based key/slot system. The OpenScad file proves you the ability to specify the length of the span, and the thickness and width. You can print male/male, male/female, female/female.

All the parameters are there for you to life the key/slot and use it in any of your designs. If you do, you'll have the ability to attach things together, with or without spans between them.

Just one more thing in a set of somewhat useful things.

1) Look at whatever you're designing and figure out if there's anywhere a key/slot would be a useful addition.
2) Print an appropriate number of these spans, or incorporate the key/slot into your existing designs
3) Slide things together appropriately
4) Rejoice!

As usual, it's press to fit. These will fit together and stay together nicely, as long as there's no real stress on them. If you want to make something permanent, you can always put a dab of glue/epoxy in the key/slot before you slide them together.