How about 'precious' items that have to be combined/reunited with their various parts to form a whole which is worth much more than the parts individually. e.g. a valuable golden chessboard set or something. The pieces could be dropped as loot or be quest rewards or some such. Theres also the possibility of having different grades of parts that you can find, so the set can be completed numerous ways with varying values. For example, if you had used a silver rook piece instead of a gold one.
The sets can be sold either completely clean, with just a few bits or the whole finished piece to a normal merchant. There would be inventory issues but then there is always the gamble about whether to pick up something you dont need at the moment but might be useful later on....
What do you think guys (and no this is not completely original, and yes, I have been playing resident evil 4 recently
