AutoBlogGreen has the details on the '08 Highlander, and it includes an EV mode! Now you will be able to move the car across the street for street cleaning days without using gasoline. Useful to be sure, but more a green merit badge on a $30,000+ SUV with real world mpg still under 30 than a significant environmental choice.
Mistakenly blaming the battery type (NiMH) for the meager all-electric performance, AutoBlogGreen remains as confused as most auto journalists about plugs and cars, plug-in hybrids, electric cars, and batteries. The 24 NiMH batteries in my Toyota RAV4 EV take the car 120 miles without gasoline. Toyota could deliver a plug-in hybrid highlander, get 20 miles all-electric and 75 mpg using NiMH today! Would a Lithium-ion battery be better? Theoretically, yes. But they don't have the hundreds of millions of miles of trouble-free real world experience as NiMH. That's why every hybrid on the road uses NiMH.
We recognize the need for cars that can use something other than petroleum for national security and environmental reasons. We need to be able to buy plug-in hybrids and electric cars now with the technology we have, not he technology we wish we had. We can't afford to wait for the perfect battery, any more than we can wait for the miracles required to make hydrogen and fuel cell technology viable.