I'll throw in another wrench and recommend trying Time, either RXS or iClic. I don't know how I would be able to pull out of my RXS pedals unless I wave my heels around (which would probably make me fall over before my feet pull out anyway). Besides, they were designed by the same guy who came up with the Looks, so you could say that they're an evolutionary step.
Crank Brothers pedals also hold really hard vertically, and they have a three-hole cleat that'll work well with your roadie shoes. They'll feel different from the Looks that you're used to, though; some guys say it's like pedaling on ice cubes.