Like Alvama's "IJN Zipang"?
That believe it or not was based on a "real proposal" (insomuch as some desk jockey admiral or academy cadet had what seemed to them a good idea then wrote an essay and a rough sketch based on it).
As for the whole Ork thing...I'm not clear as to what you're trying to do. Are you trying to cobble together real ships into something that could be the modern equivalent of a WH40K Ork monstrosity? That can get into some sticky territory regarding proper accreditation (please see the NationStates thread in AU). If you're just trying to draw actual WH40K art (which is really what any Shipbucket thing boils down to), then the rules aren't nearly as sticky since it's going to be in the AU or Non-Shipbucket folder anyway. I'm not the moderator staff so I could be wrong, but I'd even go so far as to say that battle damage would be OK on a science fiction creation, as the rule is in place mostly to pay tribute and respect to actual vessels (I don't think you can draw, say, Mad Max's Falcon
without all the grunge, for example).