I ordered one 55 lb kettlebell from New York Barbells (cheaper than dragondoor and IMHO better quality) and Mike Mahler's book of exercises (reference Mike Mahler here:
http://www.mikemahler.com). He designs a program that will definitely take your PT up a notch (no advertising plug was purposely done here..) It's amazing after all those years of traditional lifting, yet a funny looking ball with a handle can blow me away. PM if you want to take a look at part of his book. Definitely worth thinking about if you don't want to haul an Olympic set all over the place.
J