I've experimented with an enormous variety of pack saws over the years, and think I finally found my huckleberry. From Opinel of France, it's a "real" saw that locks open and shut. Has a 4.75" blade, folds 6.5" shut and only weigh's 3.6 oz's. Handle is large enough for a really positive grip. Based on their over 125 year old knife design, once again
what's old is new again: