I have a V-Max weight vest. http://www.weightvest.com/
The vest can go from 0-50 pounds in increments of 2.5 pounds. It's a nice tight fit to the chest. $199.00
Been using it for about two months for all kinds of exercises especially pull-ups, chin-ups, dips, pushups, squats (high reps), stair climbing...obviously endless amounts you can do. It's a great alternative if you can't get to the gym.