I did a bit of an update to the ProxyManipulator.
One of the key goals was to set up a nice fast foot pivot system that didn't require any fancy controllers actually installed on the foot object.
One of the weaknesses, is that although possible to manipulate an object in a perfect arc, the created keyframes will be linearly interpollated.
I have added an option to create several keyframes on the time line at ouce, to create a better arc. If you wanted an object to move in a perfect circle, you just turn this value right up.
I have also built Max 9, 2008, 2009 versions, and soon I'll compile a version for the next revision of Max.
I have also uploaded the source code. This controller is fairly simple and the source code could become a template for your own project.
Also, you coould take the code and re-compile it for whatever version of max you are using.