rebasing on top of reformatted branch

Hi,

I need to rebase a branch on top of a version that has had automatic 
formatting applied.

My usual approach for this is to create an empty extra commit after the 
branch point, then filter-branch all the commits on my branch with the 
same automatic formatting, then continue rebasing. Because the filter is 
applied to the tree, no three-way merges are performed, avoiding the 
conflicts.

Is there a way to automate this in a nicer way, especially if I have 
multiple branches that need to be rebased in this way?

    Simon