These are a few I remember from other boards, but they weren't on video, but had witnesses and in a few cases, photos -
I remember a few from the old Misc.fitness.weights days-
Rob Schuh vs. a guy from a drumming board, Schuh was a ex NPC guy and semi-pro drummer that died a year or two back. The other guy was a member of a Kiss tribute band and quite over weight.
This feud had been going on for months, so finally they meet at a local music convention, where Schuh pulls on the guy's goatee and knocks him down.
Schuh also got into a fight with bodybuilder Mike Massey over something posted on Testosterone.net, where Schuh was an early writer.
----------
Lyle McDonald got challenge to a few internet fights that he showed up for, but the other guy never did.
He was also involved in a squat challenge with a internet powerlifter Scott "Boojum" something or other that left the fella with a blown knee and hospital bills.
--------------
Titus for many years wanted to beat Dan Duchaine for Duchaine outing him on MFW for selling fake GH and schmoe stuff. They never met or it some how got squashed.
--------------
Goodrum / DA is the big one I remember from Getbig.
-------------
An interesting question that could be an add on to this, is can anyone remember any fights that materialized at shows? I recall Louie Simmons and Terry Grimwood almost fighting at a contest over an offhanded comment in the early 90's. It would've been a sight to see, as Grimwood was a rough dude, who beat a man to death a few years ago, and Simmons and co have a legit reputation as tough guys.
I seem to remember Jim Cash fought a judge over a no lift in the 1980's.
There's the famous one of Mark Henry getting into a back and forth Ryan Kennelly and Scott Yard at the Arnold, before it was squared away.