Well I needed to convert my nano (4FF) SIM Card to Micro SIM (3FF).I was baby-seating my MakerBot at the time, so instead of ordering one on Amazon, I decided to jump on Inventor and create one.
First, checked out Wikipedia on Sim cards: http://en.wikipedia.org/wiki/Subscriber_identity_module
Then - found the attached PDF at http://www.thechinacellphone.com/micro_sim_template.pdf
Quick sketch in Inventor took about 5 min - image below
Extrude. Save STL. Replicator. Print it.
Problem - the thin edges didnt come out right. Had to change the save STL defaults to high quality.