Sometimes simple is best. Have you ever tried "glue-traps?" We had a few really wiley mice in the shop that we refered to as "ninja mice." They could clean off all the regular traps, skip the others, etc. You need to find where their regular routes are, and place a glue trap. The glue has some scent added to it they like, and the trap appears as a safe object to them. We got them all first day we put the glue traps down.
One of the most ingenious traps I ever read about was a shop-vac hooked up with valves and IR sensors. The vacuum would run for a few seconds and build up a vacuum in its cannister, then sit and wait for a mouse to enter the baited hose. Upon breaking an IR beam, a valve would open, the mouse would get sucked into the cannister, the vacuum would "recharge" itself, then lie in wait. There was even a counter built into it. It was very elaborate, but effective.