Rendering shows a rear-view of the 1-Series M Coupe model including a duck tail trunk, side skirts and the quad-exhaust fitted into a rear diffuser.

Since BMW still hasn't completely unveiled the new 1-Series M Coupe, releasing instead just a few teaser photos of the car still mostly covered, here's a rendering of what the car's rear end may come to look like.

These renderings were done by automotive designer Jon Sibal. The second image shows what the car would look like when hitting the brakes and lighting up the LCI taillights. Sibal has a source inside BMW and his renderings do come with a lot of credibility. He previously rendered a front view too, which can be seen here.

The 1-Series M Coupe is rendered in Valencia Orange and on these images we see what the 1-Series M Coupe's rear bumper may look like and how the quad-exhaust fits into a BMW-like diffuser. We also get to see a duck tail trunk, which we got a hint of in the earlier teaser photos from BMW. Sibal also imagines what the side skirts, wider fenders and 19-inch rims of the M model will bring out of the 1-Series coupe.

According to Sibal, the 1-Series M Coupe will be completely unveiled in December.

The model is expected to make its public debut at the Detroit auto show next January and go on sale in early 2011.

BMW 1-Series M Coupe rendered