Never heard of Laputa before. It has a nice look to it and definitely seems ill advised.
Here are the next pics showing How I created the thighs.
The first picture shows the thigh front completed (Back still needs doing).
In the background you can see me basically putting in some placeholder pieces to see what leg sizes might work. (1 minute work, end result will look much nicer)
Basically all these pictures are back to front as I made the shape first then showed how I made it afterwards.
The 3rd pic shows how I designed the shape for the front. I had a semicircle that I rotated to the position I wanted.
I removed the parts I didn't want, then I duplicated and reversed the shape to keep it symmetrical.
In the 2nd pic I guess you could say I made a 3d mold. So I took the shape from the last picture and made it a subtractive piece. I made a box and "cut" the shape into it.
I then made this new "mold" into a subtractive piece and chopped it out of the basic thigh shape, giving the final result in the first picture.