I've got a feeling the Stern legs may be suitable for the JP. They are the black matt rough finish from memory. Just remember that Data East turned into Sega and then into Stern basically so Stern is your best bet for replacement parts I think.
Pretty sure there were one or two of the retailers selling Stern legs at the moment or check eBay and see if you can get a good pic of them to see how close a match they are.
