That is, until I went back to it tonight. I played 6 hours yesterday and saved every 30 minutes. That means 12 saves. So I go back to it now and select 'Continue'.
-No Valid Save File Found- "No problem," I thought. "I'll just use an older save from the 'Load' function.
-No Save Files- "NO WAY!!! No way has this game erased twelve saves and a total of approx. 6 hours gaming!" So I reboot my Xbox. The same thing happens. So I've made up my mind.
New Vegas is being traded-in towards Assassin's Creed Brotherhood.
I have been looking forward to this game for months and was so pleased to finally have it that I ignored some niggling in-game bugs but erasing 6 hours of my life? Not happening. So this is it. I'll get the GOTY edition of New Vegas next year when it is (inevitably) released and hope that any and all glitches and save destroying bugs are gone.
I'm sorry gamesas/Obsidian, I love you and your works, but you really screwed the pooch on this one.