You know what should be included in the game, when you kill an adamanite golum, you should be able to strip its body of some metal and take it to the slums and make adamanite armor, you'd be practically unstoppable... then you go to underdark with it, and bring that dwarf with you and have him forge drow armor into it!
Oh well, we can dream...

ToB Spoiler
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The BMU is kind of like that. It's really hard to get though, you can see this page for more information on getting it. You also get a fun gun with it, too!

Correct me if im wrong, but doesn't that stuff turn to dust when exposed to sunlight?

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Not sure about that armor, but you can get around the dusting by giving all of the drow items you want to keep to Imoen and then releasing her before you leave the Underdark. Then just go and meet/recruit her again and she'll have them all in working order and they won't disintegrate...

Which areas check for drow items? Beside Underdark exit, it is the Grove in the Ancients in ToB. Any other?

Another spoiler
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The same thing could be done with Jaheira too, unless you did all of the Harper quests. In that case she leaves for good with all equipment left on her.