Visioneer still makes it's Roadwarrior (my friends run their sales and tech department respectively, so i'm pretty sure that it's still in production).  a single usb cord provides both data and power connection so no separate power plug needed, other than your laptop.  feeds into the bar-size scanner and produces hi resolution, color scans, depending on your preference settings.

got one a few months ago for $220 and well worth the investment.

consider an alternative of using a high-resolution digital camera instead, as the copy quality and ability to transfer images into any of multiple formats with great ease is certainly available.