4 grams or 4 ounces, jarery ?
I don't think its a 'pipe dream'
EPIC encapsulated fabric technology....
a windshell made of EPIC Nextec fabric is probably your closest choice to 'universal' rain gear. It's used in single wall tent canopies and winter bivys and weather resistant sleeping bag covers. Some HARDCORE alpinists endorse EPIC fabric instead of a weather shell even for Alaska big wall and alpine assault climbing...... EPIC fabric by Nextec.
Personally, I've used EPIC shell garments in full blizzard, 70MPH wind conditions on Mount Rainier and Mount Adams during mountain rescues, taught skiing one winter in an EPIC shell, and slept underneath EPIC canopied tents on many a rainstorm now... stuff works pretty darn well.
Digging a little further, I see now EPIC fabric technologies is THE US MILITARY choice for the current GEN III ECWCS shell fabric on some of both their outer shell and insulative layers.
(way to go, Scott B.!)
more information here:
http://www.nextec.com/technology.html
It's EPIC!