Do you mean to imply that dark matter is just regular matter we somehow can't see because it's too small or dark? Because they've thought of that (obviously), and it doesn't work.
Dark matter is most likely the graviton flux that has been emanating from mass-energy since the big bang. It is literally the gravitational field itself. Gravitons are likely negative mass particles - this makes sense considering the zero total energy universe conjecture lauded by Hawking, Krauss, and others.
Interesting, can you point to a paper outlining this theory and how it matches all of the extensive observations that otherwise have supported the theory of dark matter?