Surefire just released their rechargeable SFR2 Batteries. In the past it seemed that they were ignoring rechargeable batteries in favor of their lithium primary batteries. As surprising as this is, it is certainly a welcomed announcement.
The SFR2 Batteries are lithium-phosphate chemistry which Surefire claims will retain 50% of their charging capacity even after 500 charge cycles. They only offer about 50% of the runtime that regular lithium CR123A primary batteries offer, but this should become easier to live with as lights continue to become more efficient.
You can purchase SFR2 batteries separately or as part of a kit that comes with a charger. The charger comes with AC and DC cords for wall and car charging. It also has a light that indicates the status of the charge.
Check out Surefire.com for more details.