I just recieved one today from Scott's Old Auto Rubber in Australia. It looks like a perfect match and is brand spanking new! Price was about $45 plus shipping....pretty cheap! I also got a bunch of weather stripping and it looks like a match to stock equiptment....I got the stuff pretty fast, under 2 weeks.
A link to his site is in the Parts Web Links section....if you are looking for a gasket this is the place to get it!