[BillSaysThis]

Does Optimal Layout deal with switching between single and dual monitors? That is, can I save layouts for each case and have your app switch when a second monitor comes online or off?

Yes will get you another paid user ;)

[blownd]

The layouts you save are monitor agnostic; so if you save it on one monitor then apply it on another it will be applied proportionately the same.

It's also really easy to rapidly apply any kind of custom position using the grid.

This isn't exactly what you are after but it still gives you a lot of flexibility.