You might consider a good Burley Rock and Roll. You can find them well under $1K these days, with fixed or Soft Ride stoker seat. It has 26" wheels. Probably will be 8 speed, which can go to 9 or 10 on the same hub. Ours would take 1.5" tires with room to spare and probably could have taken a 2" mountain bike tire easily. Convert to drop bars with used brifters or bar ends and there you go. You can easily use V-brakes instead of cantis if you prefer.
Our first tandem was a a R-n-R. I converted it to drop bars and never looked back for 6 years.
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