The rare single swivel seat that fits in the middle seat rails for all vans
(including Westys) is available on eBay.  The seat is brown velour, but
since the tracks are identical to those used for front bucket seats, any
other front seat may be substituted.

I have the identical seat base (with a blue seat installed to match my
interior) in my Syncro GL.  It is wonderful when traveling with 3 occupants,
as it brings the third person back into the conversation with the front seat
occupants.  Alternately, you can swivel it and talk with the rear seat
passengers.  If you have a Westy and need seating for five, this is the
ticket.

It is currently bid at $125.  Go to www.eBay,com, click on search, and check
item #590208796.
The auction ends on 5/23 at 18:54 PDT.

Usual disclaimers apply as I have no connection to the seller.  Good luck.

Budd Premack
86 Syncro, 73 Super
Minneapolis, MN (Land of Sky-Blue Waters)