It's been a while since I've been in the underdark ... *need a bg2 spoiler*

Anaximander

I could have sworn at some point you find a cache with your old bg1 gear in it ... all the remaining items that you don't find in the initial dungeon in Athkatla.

It's been a long time but I have a vague notion it was in the underdark but I'm not sure where, perhaps in the area just before you return to the surface? I also have the conflicting notion that it's supposed to be spellhold where you find your old equipment. My spellhold is modded to remove my existing bg2 equipment during the tests and you get it back just before fighting bohdi and irenicus perhaps I've supplanted the usual way things work but I'm at a loss for the time being.

Wisp

Nope. You are most likely thinking of the NWN expansion HotU.

There are mods that make you find your stuff up on the entrance level of Spellhold, and perhaps elsewhere (depending on the exact mod).

Anaximander

Well then, it's good I took the effort to slay Adalon ... hmmn interesting. Hard to replace the cloak of balduran but there's options thanx

Thrasymachus

If you pause BG2 at the very beginning, whilst the screen is dark and before Irenicus appears, you can drop any items your character was carrying upon import, and they will remain for you to pick up after Imoen rescues you.

Of course this does not help your current character!

FrozenDervish

@Thrasymachus That works with only items that exist in BG1 so your Spider's Bane and a few other items won't exist.