What is the value of a Guild bank for storage? Its a pretty hefty investment of time and gold to get a guild bank unless you are looking for one in trade casually. Often people want more for the g-bank than it is worth IMO. But I continue to look for one. I am just out of space for some of my stock piles in the 2 I already have. Part of my problem is the packrat tendancies I can not get over, and sometimes it pays off. I sold one fish the other day for 500 gold... One old BC era fish for the cooking achieve to some guy. He posted in trade, I moused over it and saw through altoholic that I had 5 of them in a bank... Logged over, one fish and 500 gold. But that is so rare.
Why do I want more bank space, well, inflation. I would like to have one Gbank for each of the following, cloth, jems, ore/bars, chant mats, and leather. So overall 5 guilds. It would make some organization really easy. Who to mail stuff to? answered, name the bank alts would be something like, "Tuxedo" for the cloth, "Jewler" for the gems, "Ironworks" for the ore/stones, "Dusty" for the enchanter, and "Tanner" for the leather.
The idea would be that I could fill up a full tab with dust from BC another with Dust from wrath and antother with lower level stuff and and another with essences or take your pick (chanter rods?) and the same with leather and heavy leather... Then each of those bankers would have the biggest profession bags possible for more storage in the bags and personnal bank... Think abou that for a second. 7 36 slot enchanting bags in the bank, and 4 more in the bag slots and the 16 slot default backpack. If my head math is correct that is 412 storage slots in bags and bank, plus 6x98 guild bank tabs for 588 more storage slots. So, about 1000, stacks of itmes per banker toon potentially. Of course lower in the professions that dont have a 36 slot profession bag like LW, 28 is the biggest that I know of currently... but still over 900 stacks of lether bought now at low prices and then sell later to the leveling profession grinders power levelers.
Really, look at the number of frostweave required to powere level tailoring or the amount of borean, heavy borean leather etc to power level a profession... then take that number and compare it to the number available in the AH... its pretty interesting, you might find stockpiling strategy gems on where the demand is going to be high, and the supply is going to be low.
The guessing part of the game is this. What professions are people going to go with? JC, enchanting and leatherworking are my guesses right now. Consider how many people will be trying to power level those professions in MOP and what the supply of mats will be.
Good luck in your stocking plans...