IMO it's the same w/ guys and girls...being able to pull of tapered jeans is not a matter of size per se but body type/proportions. Big thighs in itself is relative to the rest of your body. I'm a 32w (which is usually a no no for tapered jeans) but I think I can rock Thanaz fairly well. I just have relatively normal-size legs in proportion to the my upper body/waist.

It just depends on body type b/c believe me, i've seen some curvy girls who look stunning in tapered jeans like matics.