Brian - Don't know about the buck knife but I just finished forging a very light blade for myself about 8" long. It's not impossible to make a light 6" blade - many commercial blades are ground too thick imho.
As far as a slippery handle - that's usually an easy fix. Just take some medium grit sandpaper to it. I used to live in Boston and I found that with the cold weather up there - warmer handles are less slippery in the cold hunting seasons. Knives like the Buck Vanguard are warmer as it's a hidden tang and does not put your hand in direct contact with a lot of warmth-sucking metal. Knives like the Buck Alpha Hunter - on the other hand - are very slick and suck the warmth right out of yours fingers, rendering you fingers less sensitive and more prone to slipping.... Just a personal observation.
I will say this - as much as I love knives, they aren't guns. If it were a personal defense issue and I could carry a very lightweight gun like a .38 or one of those small .380 pistols.
Just to throw another monkey wrench into the issue - have you considered a tomahawk with a hammer head on the reverse? I've found these to be very, very handy tools for a myriad of tasks - and would make a very effective personal defense implement.
BTW - Why not take the gun, the knife and the tomahawk?
Tim