just for kicks said:
I'm kinda leaning towards having three bikes one for each of us and the tandem for the both of us.
I'm thinking the tandem would have to be a twin engine with jackshafts to freewheeling cranks.
I'm building my first, with probably another to follow for a friend of the customers. Using a 33cc Rackmount, but what I wanted to tell you was the fella priced 4 places, including some Target special, chose the Sun Drifter 7 speed from my dealer.
Sun has three choices on the website, he/I chose the 7 speed because of the lower walkthrough on the backseat.
My dealer priced it, with all my tire/wheel reinforcements and 12" gel seats, at $550-575. I don't know what kind of discount I'm getting, but the price with my adaptations were $100 less than anything my customer found.
http://www.sunbicycles.com/sun/bicycles/cruiserBikes/drifterTandem/drifterTandem.htm
The other choices were the Atlas yellow industrial type, and that third one, the Retrotandem 8)