Alliance also has access to Harpy Hide Quiver and Gnoll Skin Bandolier. These can be bought for 50 honor apiece from the AV quartermaster along the Alterac/HIllsbrad border.
afaik there isn't a panda bag (yet?), but all the other factions you only have to rep grind to revered in order to use the bag, so it's pretty easy... although dmf is right around the corner.
I think there's also 2 unique 16-slot bags you can get with honor... quiver of something and some kind of potato sack. A dwarf in hills brad... eh I'm too lazy for this right now
You can get a Mining Sack which is 10 gold without discounts that has 20 slots. However it loses most of it's usefulness once you are done leveling profs unless you want to stash away a bunch of ores/bars when dropping mining.
There is also a 20 slot Gem Sack you can get with max rep discount, but it is far less useful as we don't even have that many uses for gems.
6 Faction Bags{7 in 5.1}- Each of the core factions offers a bag at Revered that cost 2g each.
2 PvP Bags – There’s two PvP bags that are available for 50 Honor Points each.
Traveler’s Backback – A low-rate world drop from level 40+ mobs and the chest in Gurubashi Arena (and with a much smaller drop rate from Large Solid Chests in BFD, SFK, and Gnomer).