Hi Steven,
I have a small Atlas Cedar that was in a similar condition to yours about 3 years ago. It was in a small pot and it was straight, and while I was happy with it at first, I stopped being happy with it quickly. What I ended up doing may work for you.
First I re-potted it, chopped off 1/3 of the roots including all roots pointing downwards, keeping only roots going out to the sides. I then placed it on a small board in a large 5g can and left it to grow. As a note, I have had no issues root pruning my Cedars, and I have watched Jim Gremmel (the owner of the 2 very nice cedars earlier in this thread) do massive root work. The rule seems to be that if the tree is healthy, it can handle having its roots pruned. However, the tree will not develop the nebari you want if all of its roots are pointed down.
I then wired it, putting some curves on the trunk. I left the wire on for a season, until it almost started to bite and then removed it. Unlike maples, wire scars on cedars will not grow out, they will be there forever so watch the wire. This season I have wired all the branches and the tree as a whole is progressing. It probably needs another 5 years in a training pot and another 5 years working on ramification after that, but that is the progression to get a really ancient looking cedar.
As far as pruning goes, I haven't gotten to it with this little tree, but eventually when the trunk is the size I want it I will need to prune it back and train a new leader. This is a pretty good way to get taper in your tree. My understanding with cedars is that you leave a stump of about 3 inches, then when it dies off carve the stump away so the tree heals over.
This is a long process, but it has been shown to turn out some really nice trees, including both of Jim's Cedars (which I drool over every time I am at his nursery).
I am attaching a couple pics, the first is from 2006, the second is from 10 min ago. Hope some of this helps!
Cheers,
Alex