After reading some comments in another site regarding lightweight backpacking, I think I could get my day pack down to 3 ounces:

1 newspaper hat from the 5 day weather section with route map drawn on it (replaces map, NOAA radio, tinder, toilet paper, writing pad, bandana, bulky fabric boonie, Chinese fan)
1/2 razor blade (replaces knife, axe, scalpel, saw)
1 pre-magnetized needle (replaces weapon, compass, toothpick)
1 new cigarette filter (menthol) taped to 1/2 half McDonalds straw (replaces water filter)
1 sheet of scratch and sniff food smells (to make worms taste better)
1 pair edible skivvies (replaces emergency food and Fruit of the Looms) Important: keep sealed to avoid unnecessary snacking
10' used kite string (replaces cordage, belt, suspenders, fishing line, snare wire, shoe laces, bow string, zip ties, sling)
1 matchbook with motivational message (replaces lighter, fire piston, flint rod, striker, toothpick, eyepatch, Tom Brown book)
1 real shiny penny (replaces signal mirror, digging spade, sharpen for spearhead, use for barter, crow-bait, with rock pound into any copper-age implement desired)

All slung with the kite string in a big plastic beer cup (replaces daypack, water bottle, fire bucket, use for gathering berries, ant trap, grow sprouts, strap to face to make dustmask or funny noises...cut out bottom and reverse for elk call or survival bullhorn)

NOTE: Splurge! with one more beer cup and the string, you have a basic communication device...no batteries to go bad!

NOTE #2 I used the numeral forms of numbers in this list instead of writing them out...saves weight!