Spent a good half hour trying to find lens - down on hands and knees to check the floor. It was possible the lens could have fallen anywhere between the bathroom and my bed. Dang. No luck. Pulled out my spare and went off to work.
Decided to try one more check when I got home tonight. Back to crawling around the floor. Emptied out the waste basket just in case. No lens. Shook out the bathmat once more. *ping* One grey lens. Go Me!