I made some Reuleaux tetrahedra some months back.
Prior to that I made some Reuleaux rollers yoked together. Amazingly they work like cylindrical rollers when used to transport something put on top of them.
Here's a link to a short video I made: http://youtu.be/2CSpXSGFaes
And a link to the 'thing': http://www.thingiverse.com/thing:312621

All, of course, designed in MOI.

Mike.