Brother Smith sells them in 7.0, but I can't speak for 7.1 There are two female bugbears with cleavers in the temple, so you don't need to marry Fruella to dual wield them. Craft a burst effect on to them and go to town!
I discovered last night that Victor in the Archer's eye sells a plain "Cleaver". It's not masterwork and the short description says 2D4 damage, 19-20x2 The LONG description says that's it's masterwork, keen and shows the increased threat range though, so that's wrong
Must have neglected to change that, sorry. Yes, MW greats were replaced with regulars. It was in 7.1.