It has a few limitations but... its free! http://www.c4dcafe.com/ipb/style_emoticons/default/smile.gif
It will only work on deformers that are a child of the object you are deforming. So, for deformers that are simply grouped with the object they are deforming, inside a Null, will not work.
Oh, and it will only work for those deformers that do use a bounding box and you should run the script when the deformer is not yet deforming the object.
So, to test run it, create, for example, a torus or a Figure. Now, create a new deformer (a Bend, a Twist or a FFD, for example) and make it a child of your object. Now, with the deformer selected, choose "Fit Deformer to Object" from the Scripts submenu from the plug-ins menu.
Ok, enough said. I hopy you guys like it and find it useful.
p.s. For the ones that don't know how to install a script, unzip it and place it inside your_cinema4d_folder/library/scripts