I'd suggest giving ExecuCar a look. I believe they are an offshoot of Super Shuttle but they use Honda Odysseys that are dispatched to pick you up and deliver you to your destination - without trolling the airport for other fares.
Pricing is about $58 - for a party of 4, that should be a reasonable expense.
I've used them on a few occasions and they even give mileage on some airlines!