I was looking on sharpening supplies.com & Sharpton has a new Shapton Diamond Reference Lapping Plate. It has two sides to it. One side is used to flatten 500 grit to 30,000 grit Shapton Sharpening Stones. The other side is used to assist in the process of flattening blades.
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Rather than say more about it, you can see more of it here:
Shapton Diamond Reference Lapping Plate