I have done this before. If memory serves I was using a fairly standard HP all in one scanner and had no issues with quality (other than Rover and their insistence on sizing brochures just above A4 size). You just had to take that second or two to make sure the orientation was okay and the brochure laid flat on the scanner. I was saving as image files, but don't think it would be too difficult to do as PDFs.

Antp would probably be the best person to ask about storage. Obviously there are limitations on how much server space we have. Maybe it's worth using a reliable hosting system like Google drive to hold them? The Range Rover site I use for reference has the pictures hosted that way