You might look at the Antigravity 10 foot tarptent for some inspiration. I like mine a great deal.

It is a sort of pyramid with some side pullouts that give a lot more interior room. It has a beak. It also has the option of another piece of fabric that you can use to further button up the front with a fully sheltered vestibule.

One such option is an unusual poncho that can be also used to give a sheltered vestibule to the tarptent.

http://www.antigravitygear.com/proddetail.php?prod=AGTTTP10&cat=69