The website FBTB (From Bricks to Bothans) runs a few build contests throughout the year, but one of the most popular has been Steam Wars Returns. The rules were to take a vehicle from Star Wars and build it the steampunk style. This is the winning entry, from builder Marcus1984.
The Chewbacca, R2D2 and C3PO figs really sell it.
You can check out the full gallery of winners here.