If you don't use the auction house to buy/sell anything, you can still make use of it.....to store extra items.
Just go to the auction house, click the "sell" tab and then click the item you want to store. Set the minimum bid at 99,999,999,999 (or whatever, it doesn't matter*), then go to the "auctions" tab and cancel it. It will then sit in the "completed" tab indefinitely. You can store up to 50 items this way, and, afaik, they won't be deleted or anything. I've had items sitting there for over a month.
I hope this can be helpful to someone.
* For "commodities," such as crafting materials, the amount does matter because it's listed immediately. Equipment isn't listed right away, which is why the amount doesn't matter.