another option would be this:

http://www.ebay.nl/itm/191031447703?...84.m1423.l2649

it's a solenoid with some power to it.
Not sure if these will be sufficient to give a decent flip but I'm expecting two of these to show up this week to use in my own beetle. The longer you make your flipper arm will decrease the power at the tip but will increase the amount of travel.