I haven't... and no photos. However, I know a guy who basically pop riveted some aluminum angle stock to each side.... I think he used a grinder to cut some slots in the front lip, that's on the body, to allow the grate to slide in and out easily... also not sure where he got the grate from. But I must say, from what I saw of what he had done, I really liked it.
Sorry I can't be more specific... I do know having a nice upper grate would be a great addition to a already wonderful little grill.