[Pete]

For those that don't mind fabricating and doing a small amount of reading, midget and sprint race car shocks come in several lengths and multiple stiffness rates.
They can be had on many race car parts classified ad forums.
Many race teams only run them a certain amount of time and get rid of them. These are plenty good for thousands of miles on the street and they are generally quite a bit cheaper than new automotive shocks.

The fabricating part usually comes easy for most people.
Reading about stuff seems to come a bit harder.
Stiffness rates and combinations thereof are the main thing to understand.

Another BIG advantage, even on a street driven car is, this type of shock is mounted body UP which reduces unsprung weight and improves ride and handling.