Oh, just thought of another one.
There was a company right around the corner from us when I worked in Santa fe Springs that buys very large old machinery, refurbishes it, brings it up to modern technology and sells and installs it.
It's called new Century machine tools, I hired a couple of machinists away from them years ago.
They might be able to find you what you're looking for.
The largest VTL they show on their web page is 12' but I bet they get find bigger ones.
New Century Machine Tools, Inc.
BTW color me jealous. I'm in the process of buying a used VTL for my shop but it's only got a 48" table.
That's all there is in the budget right now.
But .................. my 100" Cincinnati OD grinder is just about up and running after complete $54k overhaul/refurbishment.
One thing at a time.