Bedding for camping huts and hostels

Yes. And you may or may not pay for sheets. You are likely to have to pay for towels. But nothing is standardized.

90 percent or more of the hostels provide bedding now, including blankets, pillows, and sheets/pillow cases, enough that I'd advise against a sleep sack - it's just not needed. The pillows are often flat, you may need to fold them in two to be comfortable. A towel on the other hand is a good item when staying in hostels. Hotels, even budget ones, provide towels - but I used my towel enough to justify packing it when we stayed at hostels.

The work-around on the towel business (assuming you don't want to rent one for a couple of bucks) is to get one of those fake chamois cloth things and a zip lock. Wash and rinse it real well before you stick it in the zip lock and then do the same before you use it again. A small one takes up the room of a deck of cards and works fine.

I should add that the staffed Norwegian huts that I stayed at have coin operated hot showers and drying rooms for wet clothing and boots. So yes, bring a pack towel and Kroner coins.

Don't know what the Swedish hytte are like but I would expect that they would be almost as civilized as the Norwegian. Norwegian mountain hytte may be staffed or not staffed, owned by private operators or owned by the DNT. Here is a general description of Norwegian mountain huts:
http://english.turistforeningen.no/index.php?fo_id=3610 Self-service huts include the following: "The self-service cabins are equipped with all that trekkers need for cooking and sleeping. Firewood, gas, kitchen utensils, table linen and bunks with blanks or duvets and pillows (hut sacks, also known as hut sleepers, are required!) The cabins are also stocked with provisions including tinned goods, coffee, tea, rye crispbread and powdered soup packets, but the ion can vary from cabin to cabin." American terminology for "hut sacks" is sleep sacks or sleep sheets. These are un-insulated sheet bags separate you from the hut supplied duvets. The mountain huts, especially the self-service huts, do not have laundry facilities to service hut linen.

My favorite travel towel is the microfiber towels you can pick up at Costco (under $20 for 12 or more towels) in the auto section. They're the size of gym towels we used in school. The microfiber is really absorbent and dries quickly if you hang it in an airy spot. I've paid too much for travel towels I didn't like nearly as much as the microfiber towels from Costco. Ed suggests a chamois. I pack a real chamois with my laundry stuff to wring after washing. It works great but I don't use it to double as a towel (though it would probably work well).

I was trying to describe what Brad said but didn't know the word.