I have for sale a never welded in Vanagon seat swivel seat mechanism.  Appears to be NOS.  These are NLA through VW of America, and cost around $400.00.  If you want a used swivel mechanism that is cut out of a donor Westy, look to pay $85.00.  Then, clean it up, take it to a welder, and have him fabricate the part that was welded into the Westy and could not be removed.  Or, buy this super nice and complete one for $240.00 and you are ready to install!  

Regards,

Michael Nichols
Atlanta, GA 30306