offy is the only one who makes it.  check ebay....i run across a couple every now and then....like this one http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260367315583
modello has 'em here http://www.mondellotwister.com/IntakeFuelSys.htm
here's one on craigslist...http://spokane.craigslist.org/pts/1036094403.html

and of course you could probably call tom at jbp...he'll get one for ya!