You have an inventory, it isn't a physical one... its not bound by units that represent items.

instead it has a certain amount of slots, and each slot is dependent on a unit death count.

every slot will be represented by the same unit that has its death counts modified... and every slot will be a different non-real player. Can you edit death counts for units above player 8?

(an example of my concept):
slot 1 of the inventory: player 9 unused building... 3 death counts of unused building for player nine. this slot is filled with a potion.
slot 2 of the inventory: player 10 unused building... 7 death counts of unused building for player ten. this slot is filled with and ether
slot 3 of the inventory: player 11 unused building... 21 death counts of unused building for player eleven. this slot is filled with a quest item

How high do non-real players go.... and what is the limit for death counts? if you set death counts to zero, then remove a death count... do you have negative death counts? if non real players can be included in map triggers, how so?

if these questions were answered, i think that starcraft rpg's and adventure maps would be greatly improved, thanks

You can't have death counts for above player 8. Also, if this is a multiplayer map, you'd probably want to use the death count for only the player owning the item.

Why do you need to use extended player DCs?

i really don't... i actually need help with designing a 5x5 or 4x4 inventory system where the slots are interchangeable and they are not unit-orientated. anyone got some ideas?

You mean unit-orientated as in a unit (say like a hydralisk, or marine, or critter) represents a specific item? You could use something like a combination of burrowed units to represent a certain item. How exactly do you want the system?

Well, if you were planning on making an RPG, then I suppose it could be possible...

It would be VERY difficult and time consuming, and you would have to make sure you don't use death-counts correctly. Lot's of double and tripple checking, and well as lots of patience, and, if you work like me, a LOT of papaer.

i understand why you suggested using players 9 and onwards. however, there are much easier ways of doing this. lets suggest you have 3 slots in your inventory and each slot is capable of storing multiple charges of a particular item. you will need to use 3 death counters for this, and each time you want to add a charge to an item, you just add 1 to the value of whichever death counter (slot) it applies to.

1. rename 3 unused units to slot 1, slot 2 and slot 3.
2. build a trigger to add an item to your inventory;
player: human player
conditions: (whatever conditions apply)
actions: modify death counts for current player: add 1 to slot 1 / reset conditions / preserve trigger
3. build a trigger to use an item from your inventory;
player: human player
conditions: current player has suffered at least 1 death of slot 1 / (other conditions for activation of item)
actions: heal unit / display text You used a potion! / modify death counts for current player: subtract 1 from slot 1 / preserve trigger

its really that easy. did i answer your question?