Document scanner recommendation. Large volume, 300 dpi, speed required

The project is scanning a quite large volume of typewritten manuscripts, sizes ranging from approx. 5" x 8" to 8.5" x 11". The pages are in binders and may only be scanned one at a time, an automatic document feeder does not meet our requirements.

Scanning may be done at 300 dpi, as this is good enough quality and time will be a very important factor.

Price range. Max resolution for scanning will be 300 dpi, no film scanning required. $500 - $1500. Speed of scan is of highest importance.

Scan speed is highly important. Currently with an Epson Perfection V300, scan speeds are approx. 20 seconds (grayscale), 30 seconds (color). Scan speed is then, now, 2-3 images per minute. A scanner (at 300 dpi) that would allow triple, quadruple, or more is very much desired.

Many Thanks!

EDIT:
24-bit color, 8-bit grayscale - of course nothing extreme here, i.e. 48-bit

http://www.newegg.com/Product/Prod [...] llFullInfo