Most of my trips have been in Wenonahs. Mostly in the BWCA. I buy my canoes used and they are prolific on craigslist in the upper midwest.
I sit and switch 99% of the time.
I've paddled a 16' Adirondack, a couple older Wenonah 17's in fiberglass and kevlar, and a newer 17' royalex Spirit II in the last couple of years. I feel like the Spirit II is more stable and handles larger loads better but is slower on flat water than the other 17'ers.
Don't tell anyone, but in my experience a keeled 17'-class Alumacraft will handle more weight and do so faster over water than the 17' Wenonahs. Remember, that's just between us.
I am 215# and travel with a 96# labrador. A 1989 18'6" kevlar Wenonah Odyssey has really fit the bill these last couple of years. It is faster, lighter, and hauls more than the Spirit II. It is similar to the Minnesota II but with a higher bow. I have a neighbor who loves his 20' kevlar Minnesota III for triple-portage or better trips but I have never paddled one.
I see more Quetico's and Minnesota's in the BWCA than any others. I think commercial availability plays a role there. Plenty of Alumacrafts too...
If I had the money to buy a brand new ultralight tandem, I would instead buy a used canoe or two, a Zav or two, and a new LJ or two. My Odyssey cost me $1000USD and I've seen two others for sale on CL for about the same since.
If your weight limit is 60# you are probably looking at tougher layups and not the ultralights?
I believe that Wenonah's Flex-Core layups do not have ribs. My Odyssey does. Wenonah says their flex core Minnesota IIs weight 54# and 58# in Kevlar and Tuf-weave, repectively.
If money and availability were no issue, I would buy an 18'6" Swift Keewaydin (and a Shearwater) tomorrow. They offer 4 layups under 51#
http://www.swiftcanoe.com/keewaydin-186
The Keewaydins, unlike the Wenonahs, have some rocker which I hear is useful when paddling rivers.