The best alternative to the wooden manequin is of course the 18" Super Poseable Spider-man 2 action figure. Eventhough slightly exaggerated in anatomy, with 67 articulation points, it allows you to make just about any pose imaginable.
Since I work at both home and a studio, sometimes I even go to a local book stores or coffee shops to draw, carrying the huge and heavy Spider-man figure would be inconvenient and attracts unwanted attention. I found these Microman Material Force Series.
Here's a photo of the size comparison with my PITT pen and eraser. The female figure is roughly 3-3/4" and the male figures are slightly taller. With 30 points of articulation, they are as poseable as the Spider-man figure except the fingers, but the interchangeable hands are more than made up for lack of finger movements.Male figures comes with 6 set of different hands while female figures comes with 7. Female figures are usually sold with a set of 3 pack, small, medium and large breasts size.
Microman doing Kung-Fu
Some body parts can be taken apart
Here's a photo of hands that came with the figures, and a view from their behind
Highly recommended if you are looking for good manequin.