But look at what Umbrage achieve..
Okay, I know it's a bit unrealistic to assume that that style of play would suit us, because I know it wouldn't (and takes quite a lot of the fun out of the game
IMO), but we could take a few cues from them in terms of guild organisation, we started off doing that a bit with Pug and RedPiggy's Herbalism price list, but we've sort of stopped from there..
I propose that we organise at least two instance raids per week, one for the high levellers and one for the lower levellers, another thing which would help would be if more people got onto teamspeak, we can even setup separate quest groups if you like so we don't all end up talking over each other.
Another thing, if you really don't need the cash, it doesn't hurt to give some stuff away now and again for the good of the guild.
If you're in an area where there's a bunch of mobs you can easily farm without thinking about it, farm them for a few minutes for the dropped cloth etc (if the tailors can't use it, then some of the others might need it for levelling up first aid). The same goes for ore, or leather, or anything else that guildies might need.
If needed we can always create a couple of guild "bank" characters, specifically for storing this stuff, it wouldn't take too much time and I think it would add a lot of value into the guild and make us more of a team, rather than a random group of players.
Another thing that was mentioned in chat last night was using the alliance AH as well (which is going to have a lot more stuff on it considering the alliance/horde numbers on Arathor), this could really help the guild out if we can get a reliable way of this working, as we wouldn't be held to ransom of the frankly ludicrous (for many objects) Orgrimmar AH prices.
I think most of this could be accomplished with the minimum of fuss, and wouldn't detract from normal gameplay much, if all, and would make the HEXUS.Horde a real force to be reckoned with!