I ended up with two of the Gnomes of Invention and the Troglodyte, also. When I got the first gnome, I tossed it in the shack my sim was living in at the time. Later, when I was about to detonate a pile of junk from the junkyard, I almost fell out of my chair - the gnome had moved out by the junk!
A pleasant surprise, and a very cool addition to the game.