Jason,
I too am of the large nature and have a 14 shoe. I just got my equipment for the first time a few weeks ago and i purchased the following:
Plate Shoes: Tanel 360
Chest Protector: Wilson Chest Protector
I bought this stuff at a local Umpire/Referee store, but there are several good websites out there that sell these things like:
http://www.gerrydavis.com
http://www.honigs.com
http://www.pluspos.com
http://www.wasupply.com