I actually did something similar to this on an old white Aria Pro II "The Cat".
Sprayed the entire pickguard with the pickups still attached black, then added the red "blood drops" by spraying from a distance, and holding the spraycan almost upside down. I did the exact opposite to the headstock and body.
This used to be a HSS guitar, but I swapped the neck single coil with a covered Epiphone 'bucker that came from an SG G-400.
The spray painting was done outside, on a cold, windy, pre-spring day in Norway. I actually put the guitar on some newspapers on top of some snow when I was doing the painting!
I had the neck pickup a bit too high on the bass side, so I scratched some of the paint off the neck pickup at the first band practice I used it, so I lowered it quiet a bit. I think I might raise right back up, and go beat the shit of the guitar along with some Sex Pistols music, just to scrape some more off the neck pickup, as it looks kinda lame with just the bass side shiny..
EDIT: How can I get the pictures so that you don't have to click them to view them full sized? :S