I have a toilet that has no tank. It's more like the industrial toilets you see in schools/office buildings and public toilets. I'm looking for something that is narrow enough to fit behind my toilet seat so that I can put thinks like tissue, etc. on top. I have very little counter top space in my bathroom, so I am looking for a table to go behind it to use in place of the tank top. Thanks.

Look at this link. You can find many others at other store websites.

Bathroom Spacesavers : Bathroom Furniture : Furniture : Target

You could get a small shelf from home depot or Lowe's and install it using shelf brackets.
I installed a glass shelf that has brackets. You'll just have to find the studs in the wall or use wall anchors.
Glass Clip Shelves - Wall Mounted Shelves - StacksAndStacks.com
You can also build a floating wood shelf.
How to Build Simple Floating Shelves: 8 steps (with pictures) - wikiHow
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I really love that ceramic shelf... where did you get it? A link to an online retailer or SKU number/etc would be terrific!