Is it possible? If so, how?
2 wheels == True
Maybe try the Hope 150 mm hub and squeeze the frame?
But really, I see so many of the Hope Pro 2 hubs grenading with the power of a single strong person. I couldn't imagine one surviving on a tandem for very long.
May the air be filled with tires!
Yes drop Hope an email and ask them for the part numbers.
I believe you can convert 135 to 145 and via versa but there is no conversion for 150 as the actual hub body is wider.
MTB: Stumpy, Enduro, Hotrock, Commencal Supreme
ROAD: Jamis Zenith, Pinarello Dogma