Tamiya have recently released a detail set for 1/6 bike chains...I am guessing to go with the new 'Africa' Honda. They look like they would be useful on a range of their other 1/6 kits if there were suitable sprockets available.
Being essentially flat discs with teeth and a few cut outs I imagine that they are relatively easy to draw in CAD. To that end does anyone out there have the skill and interest to draw some sprockets in CAD for 3D printing?