Hi Shawn My problem is not really about losing rankings...down to page 100 etc.. which I believe most people have and indeed you are experiencing...mine is about my URL being removed from the index.....
sorry just wanted to keep this thread on topic of being re-indexed into Google rather than optimising to get back to the first page...as there are lots of other posts covering this topic already
Wow...I did not realize you meant "missing" as in "gone" vanished! :)
I am still in the index, in fact I had a freshie tag of 11/28 a few days ago.