good point, but we sometimes delete questions from Stack Overflow and that'd also invalidate all pages (depending on how old the question was), would it not?
"Question deleted" item would help for that, and would also be more transparent for users than silent deletion (at the cost of a few more pages to show all items, becouse some items are deleted).
Mmm, that's not a bad solution, but the clutter would bother me as a user. You might just remove the items from the page (20 per page, 5 deleted on this page, now only 15) but then you might get bare pages.