Not a band feud per se, but the Norway / Sweden BM feud comes to mind.

Wasn't there something with Impaled Nazarene and the Norsk Blek Metlers too?

A strong rivalry is said to have existed between Norwegian black metal and Swedish death metal scenes. Fenriz and Tchort have noted that Norwegian black metal musicians were "fed up with the whole death metal scene"[7] and that "death metal was very uncool in Oslo" at the time.[19] On a number of occasions, Euronymous sent death threats to the more commercialized death metal groups in Europe.[19] Allegedly, a group of Norwegian black metal fans plotted to kidnap and murder certain Swedish death metal musicians.[19]

A brief "conflict" between Norwegian and Finnish scenes gained some media recognition[citation needed] during 1992 and 1993. Part of this was motivated by seemingly harmless pranks; Nuclear Holocausto of the Finnish band Beherit started to make prank calls in the middle of the night to Samoth of Emperor (in Norway) and Mika Luttinen of Impaled Nazarene (in Finland). The calls consisted of senseless babbling and playing of children's songs,[26] although Luttinen believed them to be death threats from Norwegian bands

Ah, that bit about Mika is what I was thinking of, I think.

Some interesting stuff I found.

http://www.metalhammer.co.uk/blog/the-2 ... euds-ever/

Fred Durst vs Dino Cazares
2002: From www.rockdirt.com – Limp Bizkit attempted to offer former Fear Factory guitarist, Dino Cazares, for an audition to fill the band’s vacant guitarist role following last year’s departure of Wes Borland. Dino immediately turned down the offer saying joining Limp Bizkit would be “career suicide.” Ta.

Heh, good old Dino.

I wonder if anyone would have had as many feuds or run-ins as Davey Boy. He's one of my fav guitarists and I think he's immensely talented. But, boy does he have a huge ego !

what happened? just the bands hating each other for being from different countries?

What about Iron Maiden getting into it with Sharon and Ozzy?