Well, the first thing that came to mind when I read the words, "small but powerful" was an atom. Whats smaller than the basic building block of the universe or more powerful? Splitting an uranium atom is how atomic bombs detonate.

Basicly, here's the picture

You could make the electrons and their flight paths solid, and use those as the stand. The PC itself would be the nucleus of the atom; basicly a sphere, as the bulbous-type nucleus in the picture isn't exactly pleasing.