I just tried what I assume is a relatively new product from Duplicolor.
http://www.duplicolor.com/products/headlightRestoration/
I was able to have it transferred in to O'Rielly for $10.99. It's a spray polish and a clear coat.
I had already cleaned my lenses before I bought the kit, so I can't speak to how well the polish works. From what I can tell going from a progressively more to less gritty polish is necessary depending on how bad the oxidation is. I like Novus Plastic Polish, but I've used something as cheap as Kit Scratch-out with good results.
In my case, the factory UV coating had started to peel in places, but was mostly intact, and I didn't want to spend the time stripping it all off. You can still see the line in the clear coat where the factory coating flaked off, but it's not noticeable from a quick glance. I used the polish just as a prep. step for the clear and sprayed on two coats. It goes on kind of wavy and then spreads out. It smells kind of like a polyurethane or varnish, and behaves very differently than standard automotive paint clear coats.
A couple of notes... the instructions state to use a lint free cloth before spraying, and this step is critical. I wiped the clear off of mine a couple of times trying to get them lint free. Also, the "medium heavy" application of the spray in the instructions should be interpreted to the light side of medium. Although this clear is designed to run down the lens as it smooths out, it will still run if it's on too thick. I ended up using two thinner coats. The second coat will behave very differently from the first one, with more of an orange peel effect, but smooths out nicely as it dries. The clear dries very quickly to the touch, but should not receive heavy pressure for about 24 hours. I picked one of my lights up after about 3 hours and left a light thumbprint in the coating. I would try to keep the car garaged for at least overnight after spraying.
We'll see how it works long term.
I hope it works better than the Meguiars UV protectant. I did a left vs. right comparison on my wife's G35, and it appears to be worthless. Maybe it can help protect already protected surfaces, but in terms of keeping freshly cleaned unprotected plastic from hazing again - it had no benefit at all in my case.
Heath