When I bought my D700, it was missing the rubber grip for the right thumb. Some weeks later one of my D200s died, and I stripped it for parts. The thumb grips aren’t the same, so I trimmed it with a scissors and glued it on, and it worked fine.
Ten days ago, though, it came unglued, so I decided to glue it back, only more aggressively than before. I put a fair amount of Gorilla Glue on the spot, pressed the rubber grip into place, and put a book on it to hold it down while it dried. Apparently, the pressure from the weight of the book caused the glue to ooze out at a couple of spots.
I laughed hard when I saw the result. Of course, I can just cut off the extra glue with a razor or sharp knife, but I’m halfway tempted to leave it on and tell people it’s some kind of an accessory, like the glue spots are pressure points or massage balls or something.