We have posted the Lego follow focus, the $7 Ikea shoulder mount and other homemade Canon DSLR accessories on here. This is a first though, a wooden DIY 3D beamsplitter rig.
A big thank you to Jesse Blanchard for posting the video. It just goes to show that 3D needn't be expensive - especially when GoPro seem to be bringing the editing codecs within reach of everybody.
If you are after a 50/50 mirror, Jesse bought his from stereoscopicmirrors.com
Make sure you checkout his website too, Chompers3D.com He's making a 3D horror film and will send you a free pair of red/green glasses.