First off I wouldn't do it with the switches installed.  Chances are it is just going to make a mess as it will be about impossible to mask off the switches.  If your are really looking for a painted plate and are looking to change switches anyway, I would just pony up the cash for a decent iron and a Soldapult from Edsyn.  Remove the switches, paint, and reassemble.
For painting the plate I would recommend a quality spray paint and primer.  I don't actually know much about spray paints to really recommend any in particular though.