ok, so i was reading this... and i got a great idea using bits and pieces of other peoples ideas, and a little of my own thought... so here we go:
Theres a storage agent in ur guild hall that contains guild storage. there are 4 tabs in the storage.
tab 1: All members may deposit/withdrawl any item from this tab.
tab 2: All members may deposit. Only Officers/Leaders may withdrawl.
tab 3: All members may deposit. Only Leaders may withdrawl.
tab 4: Borrowing items (explained later in post)
these tabs would be similar to the character inventory (backpack,bags,etc)
about members being able to always withdrawl the items they deposited... if they want to do that... then they shouldnt put it in the guild storage, but put it in their personal storage.
Leaders and officers may move any items between the 3 tabs, to ensure that scammers cant steal the good stuff from ur guild storage.
---------------------------
Now how to work money issues. Leaders and officers will be able to put set limits on how much a player of a certain rank will be able to withdrawl per week. for instance.
Leader: No Limit
Officers: 2k per week
Members: 0k per week
this way, a leader will be able to change money amounts to ensure no one gets more than they deserve. he could make it so members can withdrawl no money, or even that they can withdrawl as much as they want. its fully up to him to determine each kind of member and what they can withdrawl.
----------------
ok... so next one the list. borrowing! its a great idea, so i decided to include it.
When a person deposits the item, he'll have the option of making it borrow and withdrawl, or borrow only.
any items that are set to borrow only will apear in tab 4. items that are withdraw and borrow will show up in tab 1,2, or 3 (whichever the person deposited it too) and also in tab 4. obviously, certain items wont be able to be borrowed (runes, weapon upgrades, etc) basically anything that u put on a weapon or armor.
all members will be able to deposit and use the borrow feature no matter what tab a borrow & withdrawl item is in. however, the person wont be able to withdrawl the item permanently if it is in a tab higher than their access. (for instance a tab 3 borrow and withdrawl item will be available to all members for borrowing, but only available to the leader for withdrawl)
with borrow items, the item is automatically returned to the guild storage after the player borrowing the item logs out, or returns it theirself.
with borrow only items, the person who deposited this item will be the only person able to withdraw it permanently. (this way only borrow only items will need to save the person who deposited it)
-------------------------
and the final idea! access to the higher tabs may be given to members who do not meet the rank requirement by the leader or officers. officers may give regular members access to tab 2, and leaders may give officers and members acces to tab 3 by a name basis (a click on the picture in the guild list next to a members name, and click set storage access levels. then he can change what each member individually will have access to.)
---------------------------

hehe... long post by me
feel free to post any CONSTRUCTIVE critism on my ideas... BUT IF AND ONLY IF U HAVE READ MY ENTIRE POST... i dont want ppl critising my idea without reading the full idea... but if u have read the whole post, then feel free to critisize away!