Welcome to the forum. I don't have a link for you, just a suggestion: I have seen, in the past, free 3D models of Star Wars ships around the web. I'd find some of those and a free or trial-version rendering app (if you don't have one) and just do some top-down shots of them for your maps. Many renderers will let you do a render with a mask so you get just the object you want. If you can't find another app I suggest trying trueSpace 7.x, available now free from Microsoft. I think it renders to PSD format with layers.
Hope this helps!