I'm going to kill a whole flock of prairie-styled birds with one stone here. Follow the links to see the full project sets; there's too much to post here.
First up . . . Butterick 6038 (1978-1979):
First up . . . Butterick 6038 (1978-1979):

I wasn't sure about the shape, which is boxy, and the waist ties, which suggest maternity clothes even though they're not really in the right place to be maternity-anything. It felt better the second time I wore it, though, so maybe I just need to learn to be less picky about fit.
The fabric is Kona cotton, which is a little stiff but opaque enough to make a respectable white blouse. The color is "Snow" which, oddly, is off-white. It's about the color of unbleached muslin, minus the brown flecks; I wanted muslin but couldn't find any that wasn't pretty see-through. I'd kind of like to try it in homespun, too. Maybe in brown plaid with button waist tabs.
Here it is with the improvised brown dirndl skirt.

Also, that is not my house. Unfortunately.
Here's 6038 again with McCall's 5948 (1978):

Comments
I think if I were making one, I would shorten the body both above and below the ties. On the pattern illustration, the waist (well, where the ties are) appears slightly raised, and the whole thing ends higher on the hip. I think that shortening in that way would keep the proportional weight higher, making it more youthful and less "Navajo." I've been buying a few Gunne Sax pieces lately and I've noticed that the waist does tend to run high, so it's certainly in keeping with the '70s aesthetic.
BTW, I came here from Sew Retro via your post on the plaid '30s dress, which I really liked a lot. My body is not shaped like a 1930s pattern illustration either, and I really liked what you did with that. I'm off to poke around in your blog some more!
Thanks! I love the plaid dress. I have way too many patterns to sew or I think I could just make a whole bunch of those and live in them.