my tent is a http://www.blackdiamondequipment.com...ers/mega-light , with the optional floor. The tent, floor and pegs go in the rear panniers, and the pole is lashed onto the rear rack lengthwise. Much as I love this tent, I wouldn't put 4 people in it, no matter what the manufacturer says. I also wouldn't give it much of a chance in those Patagonian winds you mentioned.

For something as bulky and heavy as a mountaineering tent, I would break it up into smaller loads, with tent, rainfly, pegs and poles being distributed in a few different panniers. Poles can be lashed to the bicycle frame or to the rear rack if they are too big to go into a pannier.