desperately need to retroactively rewrite history

Hi there,

We have a bunch of directories (see my last problem) consisting of AB/,
where A and B are both in the range [0-9A-Za-z]. We want to move them
to A/B/AB, as we have solved the previous problem in this way.

However, sometimes we need to retrieve the OLD directories, but post
updates to the NEW ones. Our repo is >120,000 revisions right now
[don't ask], so rebuilding the repo would be a time-costly operation.
Is there any way to go back and retroactively correct the layout of
these files, or do we need to
1. write a hook somewhere to do the translation on checkout (is this
   even possible??);
2. rebuild the repo?

-- 
                --*greywolf;