When the worgen and goblin mount pics were first seen at Blizzcon, anyone who had their heart set on them would have 1) collected, at that time, the required battle tokens needed to get the PvP versions based on token values for current PvP mounts and/or 2) already figured out the amount of cloth stacks needed for the Donation of... and the repeatable Additional Runecloth quests to raise faction rep with the worgen and goblins and already have those stacks sitting in a couple of bank alts.
Now me, I did collected enough tokens, that were later converted to honor points, so that I can get the PvP worgen and goblin mounts. But its only been recently that I decided to do the cloth faction turn in. Why? From boredom and a need to challenge myself.
You see, after getting my toons to 80 to keep busy I worked on woefully neglected skills, raised rep with certain factions(who doesn't want an epic fishing pole?), worked like crazy in the Argent Tournament only to have to go back and raise rep with with the home factions (and honestly looking back there is something wrong when you're only honored with your own race's faction), then got to work collecting Heirlooms.
But once I got the rep and heirlooms I needed, the skills raised, and tired of doing Randoms with idiots I decided to challenge myself to collect all the cloth needed for getting worgen rep right off the bat without the aid of questing in their starting zone. (And because when Wal-Mart has Cata available at midnite when I go and pick it up then come home to add the expansion, when I get on-line and find the Worgen Cloth Quartermaster I want to at least be one of the first people who get rep with them on the first day.)
Anyway, here are the amounts of cloth needed for a high level non-human toon with access to all 4 Donation of...quests and are starting out as friendly with the worgens and goblins. (remember humans have that 10% rep increase but since I don't play human toons I didn't bother to figure it out.)
Friendly to Exalted
Now unless something changes, at Friendly you start at 100/6000 or 5900 points away from Honored.
By turning in the first four Donation of... quests which give 350 rep for each you'll then be 1500/6000 or 4500 points away from Honored. And with the first four Donation of... quests done the repeateable Donation of Runecloth becomes available.
So with that now available to go from Friendly to Honored you need 60 stacks of Runecloth.
(1 stack/75 rep x ?(unknown stack)/4500 rep. Then cross muliply and divide to get 60)
From Honored to Revered 160 additional runecloth stacks are needed.
( 1/75 x ?/12000. Then cross multiply and divide to get 160.)
While from Revered to Exalted 280 additional stacks are needed.
( 1/75 x ?/21000. Then cross multiply and divide to get 280 )
So when adding together the 60, 160, and 280 additional stacks you'll need a total of 500 stacks to turn in for the repeateable Donation of Runecloth quest. But also remember you'll need 60 stacks of Wool, Silk, Mageweave and another stack Runecloth for the Donation of....quests.
Neutral to Exalted Calculations:
Now if for some reason Blizz decides that Bloodelves and Undead will start off at Neutral towards the Bilgewater Cartel faction here are the calculations for how many pieces of cloth needed.
Starting out Neutral you'll be at 500/3000 or 2500 rep points away from Friendly.
By turning in the first four Donation of..quests you are now 1900/3000 or 1100 rep points away from Friendly. And with the first Donation of...quests done the repeatable Donation of Runecloth becomes available.
So with that to go from Neutral to Friendly you need 15 stacks.
(1/75 x ?/1100. Cross multiply, divide, and then round up the answer in this case.)
From Friendly to Honored: Because the previous 15 stacks will give an additional 25 rep going in you will start at 25/6000 or 5975 rep points from Honored.
This will lead to 80 stacks being needed.
(1/75 x ?/5975. Cross multiply, divide, and then round up the answer in this case.)
Now from Honored to Revered 160 stacks will be needed. (no additional rep points heading in with this one.)
(1/75 x ?/12000. Cross multiply and divide to get 160)
While from Revered to Exalted 280 additional stacks are needed. (no additional rep points heading into this one either.)
(1/75 x ?/21000. Cross multiply and divide to get 280)
So when adding together the 15,80,160, and 280 additional stacks you'll need a total of 475 additional runecloth. Along with the 60 Wool, Silk, Mageweave, and another stack of Runecloth for the Donation of...quests.
Of course looking at this you'll probably think 1) It does look like quite a daunting task. (But if you're bored, have room to make bank alts, I do because I only have 3 toons I'm working with right now and the rest of my character slots are being held by name holders, have an AH where Runecloth is reasonably priced, and can set aside time to run Strat Live you'll get the runecloth in no time.) or 2) I must have been so bored I drove myself insane because why else would I willingly make myself do such a thing.
Anywhich way, those are the amounts of clothes needed for getting rep right off the bat with the worgen and goblins.
When info from Beta on how much rep is given for the worgen and goblins starting zone quests I'll probably make more calculations for those who plan to use those along with the Donation of...quests for their high level toons.