Okay, so there's the Surly Pugsley, which is the only bike in this post
without a custom frame:
http://www.surlybikes.com/pugsley.html
Off-center, dishless rear wheel, 135 mm offcenter hub in the front as
well, capacity to take 100 mm tyres and, with their 60 mm Large Marge
rims, even usable with a canti, they claim.
Then there's this:
http://www.sneltweewielers.nl/news/sx1/
The Snel SX-1, custom built for the Sahara with matching trailer for a
triplet of 3-inch Nokian tyres, capacity for 55 liters of water plus 40
kilos of gear. Those water bottles you see there are 1.5 liter soda
bottles. These guys are my LBS.
And this:
http://www.m-gineering.nl/artic.htm
The Ar(c)tic, custombuilt by m-gineering for crossing Siberia and the
Bering strait and then N.- and S.-America. Running, when set up for snow,
three tyres on each end (looks like a 60-75 plus 2 47s) and the derailer
near the seat using an extra chain.
Are there any other heroically modified bikes for extreme environments out
there on the web?
Jasper