I can only assume that it will cost you an arm and a leg. Scanners seem to be going bye bye as the all-in-one printer/scanner/copier/fax seems to be dominating the market due to the ubiquity of home offices these days. I've never looked into wide format scanners but my wide format printer cost me $5,000. I'm thinking that your best bet is to get good at taking photos and then port them in to your computer.
If you find anything out I'd certainly be interested to hear about it though as it would handy for me as well in my day job.