I just posted almost the same question last week, I think its very rare that woman doesn't have this problem. I FAITHFULLY workout 5-6'x a week, cardio, cardio, cardio,
weight training, aerobics, spininng, pilates, same as you I have tried EVERYTHING!!! I am short, petite, so its even harder for me considering I don't have the hieght (4'11", 104 LBS). And I noticed the more I concentrated on my legs the more they got the "bulky look".
So I decided to train my legs only 1 a week, and even then I was extremly careful of what I did, leg presses - completely took out of my routine, I felt like this exercise really bulked my legs up. But I just started to do leg extensions, with a weight that I can do at least 20 reps. I would only do
walking lunges every other week, and I would use the fitball for 99% of my leg workout, you get an awesome burn with no weights.
However, when I noticed the "bigest' change that my legs were finally starting to look lean was when I restricted my carbs past 12:00, which is incredibly hard for me, considering I really don't care for meat, I'd rather have my rice and veggies, and skip the meat. So obvisouly I couldn't keep that up, however, i still do try.
so after all this being said, I know exactly where you are coming from, and if you can try to limit your carbs past 12:00. Good luck. I hope this helps.
Lori