We hammockers use cord made of this material for ultralight suspension (Amsteel Blue, Dynaglide, etc.). And it is almost unreal how strong it is. A 12 strand braided cord of 1.8mm diameter can reliably hold my weight with a more than comfortable safety margin (not for climbing mind you, but for hammocks). From having put together my own suspension from scratch, I can vouch that it's also incredibly tough to cut and very very slippery. It's so slippery, in fact, that it won't hold a knot; you have to use buries to put it all together.

I thought I'd vaguely remembered seeing this stuff on DIY websites for use in backpacks, but I guess I was thinking of gridstop. When I was trying to figure out if Kevlar might be better, I googled for "UHMWPE vs kevlar" and found this. That's on a cut-resistant glove manufacturer's site, so I knew it existed, but I didn't know their source. Based on the information on that page, I'd say UHMWPE is the clear winner for my application.