I lucked into a vein of Executive Proofs recently and am making them available. I love the backstory, or at least what we know of it, and I've always wondered exactly how these were used, exactly.

What are Executive Proofs? They were intentionally made by companies like Score/Pinnacle Brands and serial "numbered" with XXs as opposed to chop shop sheets from printers/vendors. From what we know, it's believed these are extremely few in number. But for the best info, or at least most trusted and credible info, can be found on baseballcardpedia under 1998 Donruss Crusade - possibly the best known examples of Executive Proofs. You can find the link at the bottom of this description.