Alrighty, It's probably not the smoothest way but it only takes a few steps to do.
So first step would be create your gradient. Seems to work best from BLACK to WHITE at 100% transparency. If there is transparency, it makes the halftones transparent. Then we will apply the halftone effect in the Appearance pane.
Since this is a raster effect, its scaling is based on your "Document Raster Effect" settings resolution, as well as the following settings. Make sure you set the angles of each color channel to the same value, you can just copy the default value in the first box to the rest of them. This keeps all of the color halftones on top of each other so that you don't get 4 color halftones, just black. Adjusting the radius value will change the size of the halftone dots.
Now you'll need to Expand the appearance of the halftone gradient. It will no longer be vector after this.
Then run your Auto Trace to vectorize it. It may take some tweaking to keep the dots round depending on your resolution settings, etc. Make sure you have "Ignore White" checked in your auto trace settings so that you're creating a one color halftone. The "One Color Logo" setting automatically does that, and may work for your needs. You've just gotta play until you get what you want. When you're finished, Expand the appearance of the trace to get it back to a vector object.
Does that make sense to everyone?