The LSS is only available (new) from Lotus. From what I've been told LSS will be available as a dealer added option at some point in the future. But the rumor that I've heard is that the price will be somwhere in the neighborhood of twice the price of ordering it originally on the car from the factory...
There are other options - there are aftermarket suspension packages being offered in Europe currently. If you're thinking about waiting and doing something latter, there will probably be something available here in the US once the numbers of cars delivered justify it - or you can order from Europe. I've also heard a rumor to the effect that John Cooper Works (same guys that tweaked the new Mini) is developing a package?
A good place to research what's going on in Europe is the SELOC web pages and their forums -
http://www.seloc.org/
BTW - I ended up, after much internal and external debate, ordering my Elise with the LSS.