Wide Format Flat-bed Scanners

I am looking for a flat bed scanner that can handle something larger than A4 size (the bigger the better), but in my Web research the units I find costs thousands of dollars! Is there anything available in a flat bed that could do something like B4 or larger, and more reasonably priced? It has to be flat bed as I am scanning objects that will not bend or are somewhat thick. Since I need to create accurate 1:1 scans of these objects, is there another technology/method that I can use to do that?