This topic is a bit old, but just in case someone stumbles across it again like I just did.
I've gathered part of this info from this Maya wireframe interface tutorial - YouTube on youtube which describes rendering wires. But you don't need to watch the video unless you need further clarification, I'll explain below:

Select desired object, in Attribute Editor, go to Drawing Overrides (believe it's under the shape tab). Check the box for Enable Overrides, turn Shading off. Alternatively you can leave shading on if desired and you'll render the vertices on top of the mesh (less control this way when going into post).

Convert your object to a softbody (this allows vertices to render). Dynamics (upper left dropdown)> Soft/Rigid Bodies> Create Soft Body (default options should be ok).
Set renderer to Maya Hardware. Batch render, or whatever you need to do. PNG or Tiff to save out the alpha.

You can also switch to Hardware 2.0 to render out the wires separately...Maya Hardware 2.0 Tab> Batch Render Options>Render Mode> Wires. Under MultiSample Anti-Aliasing, set it on and to 16 sample count.

Hope this helps

*edit* I forgot to mention, changing the color under Drawing Overrides will change the color of your wires/vertices. Also, Maya is a bit finicky when Batch rendering Maya Hardware. Don't hit the options box for Batch Render, just hit the Batch Render text.