User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-173.189.226.12-20130410174113/@comment-173.238.33.50-20130412173944

I think the maximum ammount is 300 lbs (not including armor bonuses and/or perks: extra pokets and the steed stone) maybe after all the added abilities you could have 550 lbs