I'm using nothing fancy, an Epson Perfection V39. The important part for me was a removable lid, so that it doesn't get in the way when scanning larger stuff. I'd love to have a bigger scanner, but those are much pricier. And since I don't scan THAT much myself (I'm relying on collectors scanning their stuff for me), it wasn't worth the investment yet. But yeah, an A3 scanner, with a removable lid, AND an as-thin-as-possible bezel around the glass (this one's the most difficult one) would be fantastic.
As a little update as to what I'm working now, I'm creating more color variations for the Fate of Atlantis map:
(Beauty / Box / Manual / Poster / Print Ad)
Putting hands on the map again, I've used that last color variant to rebuild one of the FOA print ads that ran in magazines back then: