I\'ve worked in a smithy as an apprentice for a couple of years (just for fun) and I\'d have to agree that a 50 lb sword is a little on the heavy side. I don\'t think we\'ve made any \"swords\" (including large fantasy/sci-fi...think klingon) that weigh over 15-20. Most are much lighter.
It is resonable to see \"barbarian\" style axes and maces that weigh 40-50 lbs. They are a b1tch to carry and will hurt yours arms after a while. One of the other apperentices takes his to the \"
Texas Renaissance Festival \", but he benches around 400+. Armor can also be very heavy. A good chainmail shirt is around 50 lbs and it might be kind of hard for a thief to take your spare off your horse and run with it (depending on the thief that is).
EDIT: Quick addon: Claymores can weigh quite a good deal and although it looks like a sword, you really use it more like an axe. Longswords, broadswords, etc. are more half-assed fencing/hacking and need more control. Foils/rapiers need the most control and weigh the least. Asian swords (katanas, some chinese swords, etc.) fall somewhere between the \"swords\" and the fencing weapons in control and weight.