Is the tach driven off the alternator
? I'm sure there are boat workers who can make you a nice custom panel, finding the right guy might be the hard part. I find often by the time you get all that sorted out, you might just as well make your own! Think about a local hot rod organization, those guys make them all the time and are picky about how it looks. Go to a Custom/vintage car show (alot of them this time of year) and they will have a name for you. Have you drawn up a picture of what you want?
The other option is to disassemble what you have and sand/ repaint etc... or maybe it doesnt have the features you want? Do you want a teakwood panel, aluminum
or like black plastic etc? Does it have to fit a certain identical space? There are a lot of brand new powerboat panels
around (companies went out of business)...