Out of curiosity...

[lesser_minion]

I know Icewind Dale II only implemented the stacking rules for A.C. bonuses. It also kept quite a lot of AD&D elements around - even elves being harder to resurrect.

Neverwinter Nights I implemented a lot more of the game (pretty much everything Icewind Dale II used, and more), but there were still differences in the rules and how they worked.

At no point in the 3.0 books do I recall seeing a rule that stated that characters are limited to a specific bonus to any given thing, but bonuses of the same type can stack.

It should be somewhere in the chapter on magic items - big table listing bonuses and their sources, and a "Behind the DM Screen" section explaining the stacking rules and why they work the way they do.

Which year was your DMG printed? Chapter 7 should be 'Rewards' and Chapter 8 should be 'Magic Items', IIRC. After that there is an appendix, which starts with a list of all items available in a large town.