See Mark's statement about Seven and Erickson building some 'custom' 160mm spacing bikes. As for Meridian (now out of business) that company was run/owned by an ex-Satana employee and did use 160s.
As Mark stated, other companies have used 160 but have come back to 145.
When you get a tandem 'custom' built you can select whatever spacing you need/desire that's feasible.
We've specced things on our tandems that many folks would not want/need; however we're not trying to please the other folks.
Heck, we get 'admonished' for using toeclips and bar ends! We also get asked "Is that a real carbon fiber rack?" Or "Are those really carbon fiber lugs on that frame?"
We have choices, and we make 'em!
Pedal on TWOgether!
Rudy and Kay/zonatandem