I'm seriously considering a Family Tandem from Bike Friday as a tandem for myself and my son to ride this season. It makes sense in that it looks like it could fit in our station wagon (instead of on a roof-top tandem rack), would be a good fit for him (he'll be seven this May), and could be used with my wife occasionally.
I've already done twenty mile rides with him on his Burley Piccolo bike trailer, and he did well. He's getting a bit large for it, and I'd like to try 30-35 mile rides this summer, and let his younger sister move onto the Piccolo (great trailer bike, btw).
As for the family tandem, I would like at least 24 gears, drop bars, barcons, good tires, etc. I bike commute and do club rides as often as possible, so doing longer rides eventually is likely as my son gets older.
So, any advice on the Family Tandem? I'd like to keep the cost around $1,500 or so to begin. For that much, I could find a used Cannondale or Burley Duet, and go for a child crank conversion kit, but then I'd also need a roof rack for it and I'm concerned about mounting and dismounting the whole thing by myself when we go out to rides.
My only fear with the Family Tandem is out-growing it too fast, but it seems like a good starting point (unless others argue differently).