How about you just press up arrow to recall the previous command, ctrl-A to go to the beginning of the line, and then type "sudo "? It's the same number of keystrokes as typing "sudo !!". And I'm sure you can use something other than up arrow to recall the previous command if you don't want to take your fingers off the home row.
Up and ctrl A are independent key strokes. They precede typing sudo, which is a logical train of thought ("Oh I forgot sudo, i should of typed sudo and then x").
! is a commonly used key in English language, and pressing it twice is fast, where as getting two desperate keys is not.
After the proposed action, you end up here:
sudo |something fishy
as opposed to here:
sudo something fishy|
which prevents you from writing an addendum to that command.
This sounds small, but I was doing what you suggested before I found out I could say "sudo !!" I immediately switched when I found out, and it's now a very common idiom for me. I switched from "up home sudo space" to "sudo space bang bang" for all the reasons described above.
