and found eBay listing for it http://www.ebay.com/itm/231213175644, thought I'd share.
Only $9.99 + 6.99 shipping (unless you live in Kalamazoo, Michigan, Local pickup - FREE!)
I went to Lowe's. I went to Home Depot. I went to Princess Auto. I went damn near everywhere on the hunt for a piece of plate, diamond or otherwise. No luck. WTF!
Back to Crappy Tire a couple of days later and picked up a $4 polypropolene cutting board, about 16" x 8" * 5/16" thick.
4 holes, 4 screws, 4 nuts and 4 washers it was mounted.
I sanded the rust off the the steel plate I have on the lazy susan and then I put a coat of Johnson Paste Wax on it to protect the metal. Big Mistake. When I tried to put down the center stand the turntable slipped out of position.