Well, 8" is standard today. 12" used to be "normal" years back...

You can make your own 12" faucet using Price Pfister 90 valves and brass fittings. This way new set up will fit existing holes exactly. No patching needed...

Thanks Milo. We found the Waltec T&S faucet can be re-worked by extending the copper tubing between the hot and cold stems and turning the center divertor tee so the spout will come out in the middle.

Thanks for your input.

Great ! Glad you've found the solution to your situation yourself ! Good luck with your project... Milo

Another option, ( I like lots of options) would be to install a Moen single handle faucet using a Moen chrome remodel plate,(see image).
Good luck, Tom

Tom, do they make those conversion plates for twelve inch center faucets, I've only seen them for 8 inch centers, but would be nice to know how wide they make them. If they do make them for twelves, I agree that a single handle would be the way to go.

do they make those conversion plates for twelve inch center faucets, Good question Lee. Moen remodel plate are designed to convert 2 and 3 hole (8" centers) valves to a single handle one.
However at 13 1/4 by 7 1/4" it might be a little tight but if the 12" holes were not enlarged I think it might just cover.