iLogic. If all your SM parts contain the required Sheet Metal Style, it should be fairly straightforward. Otherwise you just run through each part, check it's sheet metal, then change the appropriate parameters.
Add my name to the Sheet Metal multi-body campaign... Or here's a better idea, add your name to the existing Idea Station post: http://forums.autodesk.com/t5/Inventor-IdeaStation
Just seconding the comment by Peter. As for the out of box install the files would need to be changed on a 1 by 1 basis as there is no application or routine to run this type of edit for a group. This would be something useful, consider adding an enhancement request at the below link.