The British Army MVP Poncho (somewhat similar to Taslan Goretex) weighs around 900 grams so does not flap about in the wind as the lighter materials and has all the appropriate grommets etc to be used as an improvised tarp shelter.

http://www.militarykit.com/products/special_offers/british_army_dpm_mvp_poncho.htm

or the Hilltrek Ventile Poncho

http://www.hillgear.com/acatalog/copy_of_copy_of_Cabrach_Ventile_Trousers.html