You could maybe try to get a good quality pressure gauge at a hardware store en get the needed fit and pipe to make your own on as you would like it. Just an idea. Sometimes easier to make what you want in SA.
Just found this: http://www.ats-motorsport.co.za/Products.asp?section=1&CatID=27 scroll bit down
Just found this: http://www.ats-motorsport.co.za/Products.asp?section=1&CatID=27 scroll bit down