I picked up the CircuitWorks conductive pen at my local Fry's. I think it's a PITA. No matter how much I shake it up, it never mixes well. When I actually manage to get any silver out of the pen it's WAY too thick. I wish it would dry like an enamel paint but it seems to dry a little rubbery. So, if you tape sections off and paint, it's easy to pull off what you just painted when you remove the tape. :|
Maybe I'll have better luck wit a defogger ket?