Guys, on my second time going through BG2 I sussed out a way to get a load of cash without cheating.
I had my theif buy up all the master theivery potions he could find and had previously allocated him a lot of points to his Pick Pocket skill. I then had him go to the two weapons and armour merchants in Waukeens promenade and also the one on floor one above Gaelan Bael and basically steal all my party could carry (after knocking back 2 potions). I then took my party to the merchant in the theives guild and sold all I had stolen, 60K in one go ! (This guy buys stolen goods you see).
You can either repeat that or simply steal and resell from the theives guild merchant. (I didn't do this as I thought it wasn't realistic).

Viola !, lots of good equipment.

Forgot to mention, I did test it and you can steal from the theives guild merchant and see back to him