I was gifted, by a very kind soul, an old Riv Plain Musette made of organic cotton, along with the 1996 Rivendell catalog that it's featured in. Like the label implies, it's plain and simple. I'm planning to keep it in my bike bag for those instances where I need to carry just a bit more than the bag allows.
I'm wondering if folks have recommendations for other musettes that work well on a bike, but have a few more features (and more structure) than this plain cotton one that I have. Even better, if you have one you'd like to sell contact me off-list. The two that I've found so far that I like are both out of stock (Riv's current Musette and one from Handy Bag).
As an aside, in the last week I've found a new appreciation for my Riv MUSA Pants when a pair of long johns are layered underneath. I tended not to like the feel of cold nylon on my legs in the winter months, adding long johns make these pants a dream.