Some links: (search "vise" or "rigging vise" or such to locate on large
pages)

http://www.nwboatschool.org/workshops/rigging&rope.htm
http://www.porttownsendfoundry.com/id62.htm
http://toplicht.de/ (reported, they regularly export...)
http://www.maritimechain.com/supply/...bcat.cfm?sec=8
http://wireropeexchange.com/browse_c...?categoryID=56

Brion Toss may also have included a description in his book sufficient
to make you own...

Rufus