Once you get to the Refuge Hall during Act II, you'll see a Pack Mule named Bessie. You'll be able to purchase her for 70,000 gold. Once so, she has an ability called Sattle Bags, which increase inventory space by 1 for each level, even if she is unsummoned.
There are a 2 requirements that are needed for this glitch, the armor you want to wear, and an object that increases strength some incredible amount like +25.
As an example I will say the item is gloves of the Mammoth, which gives you a huge Strength bouns. Say my Strength is 103, but what I want to equip requirement is 124 Strength. I'll put on the gloves of the Mammoth , and my strength will jump to 126. (you haft to open close the armor menu for your stats to update. Now, my strength is now 126 so I can put on the Armor that I want on. Then I will equip my other gloves. and...
Wa-la! It worked!