Hey, Daniel.  I actually just ran into a little bug with this patch.
After applying this patch, if I try to scroll/search through my
mini-buffer history after a search I get the following error:

previous-history-element: Wrong type argument: symbolp, "tag:signed"

I get this error no matter what my search terms were.

Unfortunately I've always found these error messages confusing, so I'm
not quite sure where it's coming from.  I clearly has something to do
with how searches are now stored in the mini-buffer history (symbol
instead of string?).

jamie.