I looked on a website called The Rabbit House , there are a few listed that they recommend. Need to be waterbased and they recommend painting the outside only so they don't chew. Let it dry completely before they go in.
With a wooden supported run though, you'll need to paint all the wood (we have a metal run , DH didn't want to repaint)
Curinol Garden Shades Wilko Garden Colours Ronseal Woodland Colours Protek Wood Protector HS Richards Good for Woood (oil based)
The one DH used on the outside of the Pighouse was a Homebase ownbrand, safe for pets, but they don't come in contact with the outside at all . The inside was painted with a Cuprinol Petsafe in case they chewed (they haven't) but I don't know if it;s as weatherproof.
I need to buy some more for their outdoor hutch when I get it. I'm thinking of a lovely blue or green to be a bit more jazzy