Lands End has a pleated school uniform skirt available for $40 for girls and $45 for women. It comes in black and classic navy and can be bought in every size from a little girls' size 4 through a women's size 16. (It unfortunately does not come in plus sizes.) According to Lands End it falls to mid-calf, but no specific length is provided on the website. Best of all, it's machine-washable and it supposedly stays pleated after washing!
As I have noted previously on this blog, I'm a big fan of Lands End clothing. While this skirt may be slightly pricey for a school uniform skirt, Lands End often has sales (for example, through the end of today, you can receive 25% off your purchase, but sales often provide 30% or even 40% off), and the quality is excellent. If something ever happens to your skirt, you can exchange it with Lands End for a similar skirt in the same size. So, if you have multiple daughters, you'll only have to pay for the skirt once to make it last through all of them (assuming Lands End continues to produce this skirt).