It might be overkill but Project Gutenburg has an associated project "Distributed Proofreaders" at
http://www.pgdp.net/c/
Their approach is to display on the screen the scanned page in image format, and the OCR'ed text. They do make their entire system available at
http://sourceforge.net/projects/dproofreaders/
Someone might be interested in running their own personal DP website and using it to handle the OCR validation side; yes I realize that this would still leave the markup to be done separately.