I can't believe how well this actually works...
After doing a bit of googling, I discovered the practice of attaching a normal lens backward to the camera with a cheap (sub $3.00 on ebay) adapter.
All are taken with a 5d mkiii, a 50mm f/1.4 (reversed w/ adapter) f/13 aperture, a 430ex II with a cheap inflatable ebay diffuser.
C&C always welcome. This was my first attempt, so I'm looking to improve.
This is a 2 image focus stack:
Tight crop:
Tight crop: