Vix, you beautiful woman, get a grip!!
No, seriously, I don't mean to make light of your concerns. With a similar body type (except less endowed up top) I understand 100% your proportion concerns. Mine are very much the same.
But I actually did Imogen's proportions self-test and worked out (to my surprise) that my legs overall are not proportionately short! Instead, it is a combination of things: My head is big (which sort of screws all the other measurements in a way). My neck to bust is relatively long, waist is short, rise is slightly long, hip to thigh is pretty normal, but the calves are short.
Your particular measurements might be slightly different, but anyway, for me, the net result of the combination is that whatever the numbers say, I cannot see my lower legs as anything but short. They just are!! And when I put on midi-lengths, I want a heel. And even anything baggy just below the knee, I want a heel. And I can't even feel comfortable or proportioned in clams when they are tapered...without a wedge or heel. Not a high heel, but a 2 inch thing.
Not only that but my foot is similar to yours with similar fit issues. So it is actually hard to find comfortable flats anyway.
Having said all of that, I return to your photos. And what I see is not disproportionate in the least! You do not look frumpy, dumpy, or in any way bad in those flats. As others have said, you actually look about the same from the front.
BUT I agree with you that part of this is due to your skillful styling. If you were to pair them with different lengths you would look different and probably not as good to your own critical eye.
And your problem is (perhaps) that your others skirts are too long to wear with these?
Or is it a problem? Is it not okay to have a pair of shoes that you wear with shorts, 2 skirts, and skinny or straight leg pants (or slouchy tapered pants, for that matter)? I only have a couple of pairs of flats (for all the reasons you mention). And I wear them only in relatively casual or high walking situations with....you guessed it....my one or two knee length or just above knee length skirts, my knee length or above knee length shorts, and my straights or skinnies or tapered pants.
And now, you are making me want a pair of those sandals....