I've made many,many knife pleated kilts and also several kilts with military box pleats, but I've never seen that style worn for highland dancing. I did see a gent doing Scottish country dancing and the swing looked pretty good. But it wouldn't be as spectacular as the way knife pleats fly with highland dancing.
Also, I make kilts for highland dancers with hems, even for adults, because with 11-12 oz tartan, it gives a little extra weight at the bottom for a nice swing.
One way to help keep the costs down is to ask a kilt maker what he/she would charge for labor and maybe buy the tartan fabric separately through them or from someone who is able to get the trade price. Maybe you could get a discount for ordering several kilts. ???