Yes.
Finally.
At level 87 ArtDent_AGD solo killed hell Baal.
With very little help from the merc besides, I might add.
He never even once attacked Baal, just stood there looking like part of a
road construction crew if you know what I mean.  He was right behind all
my skellies ringing Baal adding his might aura, so at least he helped that
way. :)
Baal's ring of fire took out the skel mages after a bit, but all 11 skels
lived thru it fine.  I never even had to use a potion even tho the merc
did get hit every now and then by Baal's halitosis he replenished his life
before getting breathed on again.
I love Decrepify. :D
The only 'hard' part was Lister and his crew in the Throne Room.  They
took out the merc, the golem many times, and half my army before I
retreated a bit and cast a tp.  Recast the golem - again - got the merc,
went to act one Stony Fields figuring I could get my army close to the wp
so I could keep the tp in act five.  No problem there, the wp was right
above the Tristram portal with it's attendant group of
carver/fallen/whatever and a few more stray groups.  Went back to act five
all 'charged up' again, the merc had even got his might activated already,
and went back to see Lister.  It was over very quickly.  This time _his_
group was half sized, and strung out besides instead of all together.  I
blinded the minions with DV and Decrep'ed Lister.  Boom Boom Boom All
Done.
Baal did take awhile with no jabs from the mercs stick, but the outcome
was never in any real doubt.