Canon DR-5020 high speed double sided (duplex) b&w A3 scanner (Heavy - 44 lbs 20kgs) (I've now bought the colour version). SCSI-only interface so you would need to use it on Win XP with SCSI card and cable (it may work on Win7 but you will need to check). I use on an old PC with Win XP to operate some old scanners like this. I've tested that it is working. Printed manual supplied along with drivers (Win) and software. These still appear on eBay from time to time. Cost me £1,200 years ago but SCSI technology has dated even though scanners haven’t.
These are the secs: Desktop Document Scanner with Automatic or Manual Document Feeding and CIS Scanning Element
Scan Resolution Optical Resolution: 300 DPI
Scanning Resolution: Scaleable from 200 to 300 DPI in 10 DPI steps
Max Scanning Resolution: 400 x 400 DPI
Color Processing 8-bit , 256 levels Grayscale
Scan Speed 90 PPM (Letter Portrait @ 200 x 100 DPI)
Misc. Features Scanning Mode: Simplex/Duplex, (Text/Photo/AE)
Count Only mode for simple document counting and quantity verification without scanning.
Simple connectivity with a choice of three included drivers: ISIS® and TWAIN from Pixel Translations, plus a Canon proprietary driver.
Function Sheets allows the scanner to automatically set predetermined scanning modes for enhanced productivity
Optional Imprinter prints specified numerals, characters and symbols at any position on scanned documents.
Optional Endorser allows users to print up to 6-digit character strings on documents as they are scanned for verification.
Optional Bar Code Decoder may be added to the DR-5020 for automatic interpretation of bar code symbols.
Stacker Capacity: Approx. 500 sheets (80 g/m2, up to A4/LTR size)
Document Size Max W x L: 11.7" x 17"
ADF 500 Sheet ADF Unit Allows Duplex or Simplex Modes
Connectivity SCSI 2