According to a report from Wired's Autopia site, the Tesla Roadster that we are familiar with will come to the end of its production run in 2011. A new version of the Roadster will appear in 2013.
Autopia came across the information while perusing through the filings made by Tesla with the Security and Exchange Commission. The filings were necessary as Tesla had to submit paperwork for its IPO. Within the paperwork, Autopia found these statements that appear to verify the future of the Roadster.
"We do not plan to sell our current generation Tesla Roadster after 2011 due to planned tooling changes at a supplier for the Tesla Roadster.... As a result, we anticipate that we may generate limited, if any, revenue from selling electric vehicles after 2011 until the launch of the planned model S..."
The Tesla Roadster is built at the Lotus plant in England. The Roadster shares its underpinnings with the Elise model. It's highly likely that Lotus will be replacing the current Elise with a new version by 2012-2013 which means that Tesla will not have a chassis available for their Roadster as Lotus prepares for the changeover.
One possible problem could crop up at a later date. The Tesla Model S in not due for release until 2012 which leaves a gap with possibly no vehicles for the company to sell from the time that the Roadster exits production until the time that the Model S enters production. Without a model, Tesla could face some financial difficulties. Additionally, any delay in the Model S would become problematic.
The all new Roadster will go on sale in 2013 so those interested in a Tesla offering will have more than one choice by then. Look for additional information about the next generation Roadster soon.