On November 1, 2011, all Drupal 8.x core files will be moved into a /core folder. This will break nearly every patch in the 8.x queue, requiring them at least to be re-rolled against the updated directory structure.
After that date, backporting 8.x patches to 7.x will no longer be trivial.
I've looked at this and I'm comfortable with the patch. Given that it may break a lot of patches, I'd like to propose that I commit this on November 1st, 2011. Like that, (1) we don't break all patches in the issue queue just before we all go to DrupalCon London and (2) we give ourselves a bit more time to stabilize Drupal 7 with minimal effort.