In the event that I foresee myself traveling in country such as the Inuit do, where a persons clothes must remain intact to avoid freezing while moving about (on the hunt perhaps), I will add a strong needle and a length of strong thread (in case I must leave the shelter, thus exposing myself to the freezing arctic winds). My response may sound a bit sarcastic, and it may in fact be, but still, just because the Inuit may highly value a sewing kit, doesn't mean that they sleep in their clothes. I learned early on that a shelter is the first priority in a survival situation, not being able to fight the artic winds on my way to the nearest town. But then again, different people foresee different scenarios. I'm not saying you shouldn't carry a sewing kit or a sewing machine for that matter, but I won't, only because I don't foresee needing one, not in a PSK, regardless of the minimal bulk and weight. Why not carry a toothpick? They weight next to nothing and might come in handy too! Oh, and what about a bit of wire and steel wool in case you decide to use your flashlight batteries to start a fire. Why use a lighter when in a survival situation you can really justify using all the tricks of the fire-making trade. After all, those items weigh very little and even the wool can be compressed so it doesn't take up much space. Wow, and how about a single .22LR bullet (the gunpowder can be used to start a fire), and a magnifying glass too! What about a few coins so that you can make a phone call, or a calling card for that matter, both of which take up very little space.
Anyways, my PSK is very small, I don't even know I'm carrying it because it isn't any bigger than what I absolutely need. Less is more. By the way, I enjoyed reading all your responses, and I'm not knocking any of you. Autonomy is a great thing, but I can't justify accessorizing my PSK to personally fanciful tastes, at least not in theory.