Talked to a very nice saleman at Tractor Supply today, about havaheart traps for really small critters. (this is, by the way, not the season to visit this store if you have a low tolerance for poison baits, traps, hunting gear and deer bait stations) and we discussed various methods of mouse removal. He's a fan of electric shock. I'm a big fan of catch and release, let them work their own way home.
He suggested a tall pail with a bait lure and a little walkway to get them up and over the top. As he said, they can't leap high enough to get back out. In thinking it over, I realized that they can't, but my cat can. Good idea, poor ending. However-- I have a faux composition garden pot that is big enough and tall enough to trap a mouse or two, and if the top were closed off, and upended, there is a drain hole in the bottom they could enter, and be trapped that way. Paws could enter, but not entire cats.
Stay tuned. It might just work.