As far as the respawn problem goes, I believe (haven't played on these servers, but I'm assuming) they have LDoN (lost dungeons of Norrath).  What that expansion did was give a big bunch of instanced zones specifically designed for dungeon crawls like you mentioned.  The mobs are spawned for your group, and once you kill them, they stay dead.  I wish the rewards had been better, because they really were a blast to play.  There are other instanced zones in other expansions, but LDoN was all about the dungeon crawl.   
 
Hope that helps. 
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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