I run a newly started FLGS in Rhyl, North Wales, and one of our opening events was to have a painting competition using a standard marine that was handed out for free in-store. The only part of the model that was permitted to be modified was the base, other than that, everyone...
I put together this diorama for the P3 Grandmasters competition at GenCon. He was awarded a silver medal.
By the way, I've put him up on CMON if you care to vote.
Overall, I was pretty pleased with how he turned out. But don't take my word for it: