I wonder the same thing. Mine is beautiful on the toast, and I'm hoping it doesn't need replacing in the near future.The 300C looks like it might be viable with the right drilling and surface.
My home shop has a NIB Mars sitting on the shelf. He's had it for a while, so I'm thinking he'd be reasonable about the sale price. If you want to take a stab, call 815.939.2695 and ask for Lance.