How about something like this?

![Dot matrix example][1]

Or, even more fun:

![Glowing dotmatrix – what could be better!][2]

Or a ball:

![So much fun][3]

The dot aspect ratio depends on your UV unwrap, so you can customize it as you want. I have gotten them to be square, but having a square image makes it a lot easier.
Workflow:

 1. Identify the nearest hole.
 2. Find the distance to the hole.
 3. If the distance is greater than the radius, use transparent. Otherwise, use the central color of the center of the hole.

Blendfile: [link](https://www.dropbox.com/s/0g0qossrgw5gzia/DotMatrix.blend), [mirror](http://www.pasteall.org/blend/24812).

**Usage:**

![How to use this node group][4]

**Main node setup** (right-click → *Open Image in New Tab* to see larger)**:**

![Main node group, "DotMatrix"][5]

**Separation (top) and combination (bottom):** (would be nicer if it were built-in)

![Node groups "Separate Vector" (top) and "Combine Vector" (bottom)][6]

**Distance:** (Pythagorean theorem/Euclidean norm)

![Node group "Distance"][7]


  [1]: https://i.sstatic.net/Xw2mj.png
  [2]: https://i.sstatic.net/q78Db.png
  [3]: https://i.sstatic.net/mwba4.png
  [4]: https://i.sstatic.net/qAEgQ.png
  [5]: https://i.sstatic.net/7LmB9.png
  [6]: https://i.sstatic.net/GTsTl.png
  [7]: https://i.sstatic.net/snphU.png