What are my options in terms of a good 4x5 camera that is lightweight and compact? In Alaska, I biked 20 miles with my Horseman monorail along with 20lbs of other equipment on my back. It was a bit painful to say the least. I'd be interested in getting a nice compact and sturdy camera for these situations.

Also, I don't want to spend more than $500.00 used so those Arcas are out of the question

Just interested in knowing what you guys are using and what I should look for or avoid.

THANKS!