Niche Domination Strategy - A question

[Nathan Hangen]

I've been plotting and planning my future niche domination strategies and there is something that I'm not quite sure about.

At first I thought it would be nice to create a new site (10 articles or so each) for each keyword, and then use SEO to put them all on the first page. Then I got to thinking that maybe it would be better to just use one site and have it dominate every keyword on its own. It wouldn't hurt to have lenses and other blogs (blogger, wp.com) on the first page either.

So my question is, let's say I want to dominate a niche in order to sell it down the road. Am I better off with different sites for each keyword or using one site to dominate every keyword?