We have a Black Welsh Mountain ram lamb, born in March (I can look up exact date) that you would be welcome to borrow. Obviously I can't guarantee he's a go-er; but I'd happy for you to apply raddle paint to him and see what happens! He's a lovely looking lad, still in with his Mum at the moment, bucket trained but a bit skittish.
I have a photo but my phone won't let me upload it!