This is a very stong shelf rack: http://www.target.com/p/Whitmor-Supr..._page.embedded
It holds 250lbs per shelf and a 10gal fits perfectly. You can actually fit 2 10 galons, one on top of the other and still have one bottom shelf of about 6 inches for fish supplies.
I used to have one set up just like that, you just have to measure well where you want the shelves because they are not the easiest to take apart.
It comes in black, silver, and white and it's usually much cheaper if you go to the store.
There's also a larger version available.