There is one company that sells on ebay that makes a spatter paint that you spray with a paint gun. Comes in a quart can... I think it's water prrof as it's more of an oil based paint I believe (been a while since I read their ad?) so don't quote me...

Ok, here it is, The Parts Place Inc. out of Ill.
http://tinyurl.com/amqhg

But at $60... it's a bit spendy?

Brett - 67 Drop Top 455!