It looks like SEMA and the State of California have come up with a plan to address specially constructed vehicles in California. SB100 will continue in its current form, but they will now offer two other options. A complete GM (only complete drivetrain opton available at this time) LS3 powertrain package ($7,900) that meets smog requirements will be offered or you'll need to buy a "green rod" kit that costs $6,000.
This might work if you want to build a mild Hot Rod to cruise around in, but the new option probably won't fly with average Cobra buyer. The 500 SB100 exemptions will still be the only option for most people.
SEMA and California Agencies Solve Titling Dilemma for Hobbyist Vehicles
http://www.sema.org/news/2009/11/02/...byist-vehicles
"How much should I expect to pay for the “retrofit” kit? How much should I expect to pay for the GM engine and powertrain?
The retrofit kit is a collection of emissions-related parts with specifications developed by SEMA for which a variety of aftermarket manufacturers will be able to supply components. On average, the kit should cost approximately $6,000. The labor to install the package will likely cost an additional $5,000. If you choose to use a new engine and powertrain package from GM, the current LS3 package will retail at an estimated $7,900. GM will also offer a number of other emissions-approved engine packages with a variety of performance options and price levels. Estimated installation cost for the GM system is approximately $6,000."