I am looking for one also, because I am considering changing to a black pickguard,
I found this, It a company that make custom replacement pickguards.
I have not ordered one from them yet so I can't tell you what to expect.
I found somewhere on their site that you can order a mock for $5 up made out of paper or cardboard to check fit.
here is the link for a real pickguard.
I printed out their PDF at Staples and cut it out last year to check the size. I think it's for the the older vintage plus guitars, as it did not fit. Staples could have possibly printed out the wrong size. I told them to print it in the actual size, so it should have been correct. Supposedly they sell official replacements in Japan, but none of the ESP Japan related stores will reply to my emails. Will likely have to pay someone to mod it and drill new holes.
So I got my black pickguard from Terrapin. All the screw holes matched, but I did have to shave the neck pocket slightly to get it to fit. May have over shaved it by just a hair, making sure it wasn't too tight, but it looks good! I'd rather have it a little loose anyways, as I don't want the plastic rubbing on the neck tightly and damaging it. Overall I'd say they did a good job with it, the material had a few marks on it after I peeled off the plastic, but nothing terrible or worth complaining about. I'd say go for it, as long as you know it will fit your Vintage Plus.