Kinda tough to do anything if the City Council isn't on board.
The best option I've ever come across for "traffic calming" was in Edmonton. They had a grid layout on streets in parts of the city, and they had constant problems where people would get off the main road, and be zooming along the side street which paralleled the main road.
The city hit on two options. One was to put these long/shallow speed bumps in the road. Not the 12" wide 4" tall bumps that you get in parking lots, but bumps that were about 4 FEET wide, and just a few inches high. At moderate speed you barely notice them, but if you hit them at any speed it feels like your car is about to fly off into the air. Very disconcerting. (or so I'm told.. )
The other option they had was to put LARGE planters along the side of the road. (see the diagram below) These would intrude a bit into the road and force you to wiggle your way around them. Again, they could be positioned so that at a reasonable 25-30mpg you could cruise around them, but at speed... forget it.
traffic-calming.jpg
Other than that, I'd suggest things like rumble strips, or a big fluorescent sign that warns of the hill, or maybe get a flashing amber light installed.
Of course the geek in me would rather that they install radar activated spike belts that emerge when it detects a car at 5-10mph over the speed limit...