Of all of these suggestions, I like the "...it was on back-order" one the most. I can see dropping that rather nonchalantly and having it succeed.

One of my faves is the "...I had to act fast here! They've stopped making these...if I didn't order it right then and there, I would never have been able to get my hands on one. Why...it's a collector's item now...".

Best

AA