I'm just curious about why?
Why would you need a stem greater than 35 degrees and longer than 150mm? At that point, I think you'd want to start looking for a new frame.
Our travel case can only fit a fork steerer tube up to a certain length. About once a year (maybe every other year) we have a customer who wants the bar higher than the max steerer length and 35°, 130 or 150mm stem gets it. Those customers have to remove the fork from the frame and pack it in a seperate bag. As a mechanic on the tours I've seen a couple bikes like this. To me that kind of defeats the purpose of the Santana Safecase & Z-coupler system because it's normally such a simple and elegant way to pack a travel tandem. I'd like to offer those guys a solution that lets them put the handlebar where they want and still pack the bike as intended*. Who knows, maybe no one will choose it cuz they prefer the look of a more traditional stem and tall steerer and are willing to deal with a little extra packing hassle.
Also remember, 150mm isn't very "long" when angled up at 35°+. The Safecase doesn't limit top tube length within reason, only steerer length. It was designed before the age of foot long head tubes.
It sounds as if Ti guys like Erikson or Moots are the only option. Or one of the steel stem guys. I just wanted to make sure I wasn't overlooking anything.
*I realize handlebar risers and steerer extensions exist but those are even goofier looking than a 45° stem and probably heavy and flexy.