Jane,

Glad you liked the links. Let me address some of your questions and give you yet more links!

The Burley Piccolo is expensive (about $360, including the rack) and rugged. Most of the seatpost mounted trailers have some slop in the hinge, a problem that tends to worsen over time. Adams also for several years made a tandem trail-a-bike (two kids), but those would be a real handful behind a single bike, let alone a tandem.

Strong rear wheels can definitely be an issue. Most of the discussions I've followed tend to recommend: 1) High quality hub, 2) 26 inch wheel size more rugged than 700c, but you would be limited by frame you already own, 3) Deep section (aero) and/or wide rim (like Mavic T520, Sun Rhino Lite, Velocity Deep V or Velocity Dyad), 4) 48 or 40 butted spokes, and, most importantly, 5) built by a reputable and knowledgeable builder (Peter White in NH, Mel Kornbluh in NJ, etc.). Most wheels are poorly built, and will not last. Well built wheels are wonderful and worth the added cost. Wider tires (28, 32, 35 mm) better absorb road shock and cushion the rims.

Family of 5:
http://www.rompfamily.com/

Easily configurable and shippable family triplet:
http://www.bikefriday.com/bikecat99.cfm?cat=11

Our longest family ride has been about 20 miles, but we hope to boost that to 30 next year. We're not (yet) into camping, but there is plenty of gear out there that would be suitable.

S&S couplers make transporting loooong bikes possible. See the following:
http://www.precisiontandems.com/arts&sbysteve.htm
http://www.co-motion.com/travmenu.html

Mark Johnson, of precision tandems (ya gotta see this guy) has a quint (5-seater) with S&S couplers than can also convert to a quad, a triplet, and a tandem.

Good luck,

herhusband