There are several companies that are making deeper (30mm) Al rims these days. They give you a lot of the benefits of deeper carbon rims without the cost and extra care that comes with carbon. Look at the Boyd Altamont, Flo 30, and Zipp 30. I'm sure there are more. They range in price from $500-$850/set and weight 1500-1700gms, or there abouts. They all have wider rims also, which means you can run lower pressures, get less rolling resistance, get better handling, and a smoother ride. Are you sure you need/want carbon?

There is an article on Flo's website where they ran simulations on different wheels on different courses, comparing how heavier vs. lighter wheels performed, and aero vs. non-aero. Aero always won vs. weight, no matter how hilly the ride. Taking all this into consideration, I got the Flo 30's for $500, and I'm sure they're all the wheel I'll ever really need. You may be a more serious cyclist, or have different goals than me. Good luck with whatever you decide.