I finally ordered my first crayon holder I designed in WSF (here: http://shpws.me/3kM1) and I can't wait for it to arrive. I'd like to thank Jeff Bare (@jbaredesign) for lots of advice while I was refining this design. Let me know what you think!
I've updated the design a bit after printing the first piece, making it slightly larger to fit the crayons better. The updated design also has a few "windows" cut into it to reduce printing volume, and therefor cost. Here it is: http://shpws.me/3mT6
I also made a scaled version intended to be used for pencils, but I have not yet printed it out. Being smaller, it is a bit cheaper still: http://shpws.me/3tvz