I can't address the 5 simultaneous user issue. But I do hope it is not true.
As far as excessive scanned documents, this is a matter of the amount of time it will take to copy the files to another source for backup. It should be a problem with any EMR (or anything else you want to back up). It takes time to transmit the data to a different pc or external drive. The more data,the more time it will take. But you seem like you have ALOT of pictures that you want to scan in. It sounds like you might need to have a separate system for storing high-quality images (I know you don't want to hear that).
