While I am not a framebuilder, we have designed several tandems through the years to fit us by such competent builders as Matt Assernmacher (Michigan), Colin Laing (England and Phoenix, AZ), Co-Motion (Eugene, OR) and finally, by Bob Davis (ariZona Tandems) a carbon fiber specialist (Peoria, AZ).
A good framebuilder is a competent craftsman/artisan/cyclist that can take people's ideas and turn them into reality.
Back in 1977 Matt built us a tandem to our specs, that weighed in at a then incredible 34 pounds; pundits/experts said frame would break; they were right, frame broke at 50,000 and 56,000 miles.
Colin built us the most incredible work of rolling art with mixed tubing and handmade lugs (that took him 40 hours to craft) + an experimental fork.
Co-motion did the most seamless fillet brazing and custom building and paint. That's when it was still 3 guys (Dwan/Dan/Butch) working out of a converted garage).
Bob, who runs a 1-man shop, built us an amazingly light/maneuverable/comfortable (26 1/2 lb.) c/f 2-seater with such exquisite details like a 'retro' carbon lugged frame (with window cutouts), and such innovative/prototype ideas as adjustable c/f stoker stem, stoker pegs and a one-of custom c/f rack.
Yes, we paid more than an off-the-rack machine adapted to fit us; instead we rode a custom fitted/built machine reflecting our wants/needs.
Quality will outlast mediocrity any time!
Pedal on!
Rudy and Kay/zonatandem