Depending how much room you need and how important the stuff is you're storing, a hitch platform might be another option. I couldn't justify the weight or expense of a Stowaway so I bought a lightweight aluminum hitch carrier and a waterproof cargo bag. It's really a perfect combo for me. If I ever absolutely needed that extra length back, and I almost did last week in a REALLY tight parking situation at a music festival, I could remove it all and stash it in the shower temporarily.
This is the bag:
http://www.amazon.com/gp/product/B00GA2HKQYAnd this is the carrier:
http://www.amazon.com/gp/product/B004QEKG8CI got the one with the folding shank but I'm not using the folding part. It seemed like a good idea at the time but when I installed it I decided the added length & instability with the folding shank really wasn't worth it. I still have it if I ever change my mind, as has been known to happen. :-) I got this on sale before Christmas so it was only @ $75
I initially bought a HUGE bag for it.
http://www.amazon.com/gp/product/B005CVZOPSIt was too big. I couldn't move the ladder & get into the storage if it was full. The smaller one is perfect.
It hadn't been installed yet in this pic but I got a Plate-saver frame & mounted my license plate on the carrier. Also, there's more space in the bag, the boxes are 12" high and the bag is 18". So it does expand to be a little taller than shown.
The thing I like about this setup is it's flexible. I can carry an item bigger than the carrier or bag if I need to. If I need it off for whatever reason, it's a moderate pain but doable. The bag & carrier together weigh about 20# so easily movable. If I need to put bigger items in the bag than the boxes allow I can yank out the boxes & fold them up again. If they get dirty or wet buy new ones, they're less than a buck apiece. Downsides are, it's not for expensive stuff as it's not lockable. Also, while it hasn't leaked yet, I'm not putting stuff in that won't survive a few drops of water. As time goes on I might find some plastic tubs that fit but it's not a priority.
