Well, after some more testing with the items i committed the changes, but only after fixing another issue. I was trying out the summon spells, since they summoned a wrong amount of charges. I got to try out gift of xev, it summons a bag and bandages and food and stuff. So i put the bag in the inventory, opened it, and wanted to put in the food,drink and bandages i got on my cursor.... well but the client said item to big..lolwut? Then i tested other bags, and even tinkerer bags were "tiny" - i.e. only tiny items could be put in.
I checked the loading code from the database and it seemed fine, i didnt understand why the bagSize was always 0.... well after a while it turns out it was a really stupid mistake. I was always fixing the race/class bitmask (see earlier posting) at the very end of the loading code for each item. Well, however these fields in the item struct are only used by "normal" items, not by books or bags. When you set the race data in the struct, you effectivly overwritting the bagSize property cause they are both at similar position in the itemstruct bytewise. So it went like this: load item from DB -> ok its a bag -> set bag attributes -> do stuff -> finally set race/class bits == same position in struct as bag attributes -> overwrite these values again (with 0 in this case = 0 = tiny bag size).
It must have been a design decision by verant very early to missuse the same struct position of an item depending on the item type - to save some network traffic i guess.
As far as summoning items is concerned i only found one spell which really have a level based code for the amount of charges returned -> summon bandages (level/2) - any other spell would always return the max value regardless of level (20 arrows/daggers/food/drink for Cornucopia and co).