I just bought armor with 4 lots. That's the only four slots I've seen. I'm in Act 4 too.
I'm now trying to get enough money to buy 4 Yits to go in it. In addition I have three more Yit slots to fill in an amulet for my DK. I have some powerful non slotted items too. I don't know if even with 4 yits, the 4 slot armor will measure up. It hasn't got much else going for it except slots.
I hope I get the gold to fill the slots before the game is over. Act 3 was a real rip off for gold, with all those unsellable oaks and quivers.
Personally, I like older games better where when you found a treasure, it was a treasure. You didn't have to weigh +2 str against +1 int and +1 const....
