I received a few very helpful answers from the SCA-JML mailing list.
But first, a site I forgot to link to yesterday, the Wodeford Hall.
This page is about The Kosode: http://www.wodefordhall.com/kosode.htm
This one is about painting and printing fabric: http://www.wodefordhall.com/fakingit.htm
Now, on with the replies!
Tekko and kyhana are for warmth or other protection. If you don't need them, don't bother.
Photo of me slumming at Pennsic two years ago, shows me in a single layer of linen with an obi that's a bit fancier than necessary. http://farm3.static.flickr.com/2234/2025863270_74473d5064.jpg
Note that this is a case of one of my regular kosode doing "double duty". It's big enough and long enough to wear as another layer with some of my others for an impression of higher status, but simple enough to wear as shown in the photo.
In general, peasant kosode will be a bit shorter - mid calf would not be an indecent length and you can achieve that either by hiking it up (as I did) or by cutting yours a little shorter, and maybe an inch narrower than someone of higher social status. Linen is a good substitute for hemp or ramie, two bast fibers which the Japanese had and which the lower classes wore.
Tasuke is a method of tying your sleeves out of the way. It's extremely practical and fairly easy to do once you know how. A strip of bias tape works great for this. Scroll down here to find a photo how-to:
http://www.tnm.go.jp/gallery/search/images/max/C0022482.jpg is a detail from the great "Genre Scenes of the Twelve Months" screens in the Tokyo National Museum, dating from the 16th century. It shows women transplanting rice as musicians play and drum (a scene replicated at the end of Kurosawa's "Seven Samurai.") Note that hems are at the knee, sleeves bare the arms up to the elbow and if you look carefully, you'll see painted tasuke - it's easiest to pick out on the planters in black as their taske are red.
An accomplished textile artist can dye, weave or otherwise decorate the fabric in bolt form. I freely admit to cheating when I paint by cutting out my fabric and doing partial assembly so I can lay the thing out over a table and line things up as I apply the decoration.
When asked about Shogun, she said:
Caveat: Films are not documentation, though they can certainly get your inspirational juices flowing. I haven't actually seen "Shogun" since its network airing back in the day. However, I've gotten this question enough times that when a paperback "making-of" edition turned up at a local book store, I acquired it. There's a photo of the costume designer displaying one of his production sketches next to a book containing a 17th c. painting that I recognize. "Shogun" was a a cooperative collaboration between a U.S. and Japanese production company and they did a good job in terms of production design. The women's costumes, particularly the procession of pink, floral stuff worn by Yoko Shimada as Mariko, strikes me as the evolving 17th century style, particularly in regards to the width of obi (looks about 4" to me), worn tied in a soft bow at the back, and the softer, less stiff fabrics used.
I've been watching a lot of Kurosawa this month, thanks to a local film festival, and the period costuming in many of these can also serve as a point to start from. Here are some stills from "Hidden Fortress" of a young peasant woman, that match reasonably well with the rice pickers in the "Genre Scenes" screens as well as some of the Kyoto Costume Museum items you posted:
http://www.kurosawamovies.com/gallery/d/3025-2/hidden43.jpg has a better shot of her head wrap, which can be achieved using a square of fabric folded in half on a diagonal.
Then, booknerd9 (sorry, you didn't sign your name) wrote:
I wear a kosode and mobakama for pretty much everything. You can also tie the sleeves back and this keeps them out of the way quite well. However, if I'm in the kitchen, I tend to wear a mundane apron because I'm neurotic about getting stains on my garb (;
After that, I received another answer from Saionji:
The men's stuff from "Shogun," is not stylistically different from pre-Edo, but the women's clothing is definitely showing the evolution toward the newer styles.
And finally, after I said: I've been able to take a look at the Kurosawa pictures and I have a question. On this one: http://www.kurosawamovies.com/gallery/d/2995-2/hidden33.jpg. The sleeves appear incredibly narrow, almost like a tube sleeve, t-tunic style. I thought the sleeves look rather narrow too on the KCM pics. What do you think?, Ii answered the following:
"Kosode" can refer to either the tube-sleeve look or the more distinctive curve--it really seems to refer more to the opening of the sleeve mouth than the rest of the sleeve. That said, having a little extra fabric looks more posh, and became the standard. Looking closely at the image, this is a more traditional sleeve, with the curve, but you are looking at the bottom seam nearly head-on. Look at his left sleeve and you'll see the characteristic "v" tail shape, and you can follow the straight lines across to see that they are just all being pulled upwards. It is small and peasant-wear, but it is still there.
I think this pretty much answers all questions I had! I promise to write the next post myself ;-)