For this pose:
http://www.thedentedhelmet.com/showthread.php/36189-My-Boba-is-almost-done-now!-99
I just bought a mannequin from ebay and cut the head, and the arms to re-position them. I used heavy duty tape to keep it in the pose I wanted it and fiberglassed the arms again. After 30 minutes it was dry and hard as a rock. It´s no problem to put the ee-3 blaster into the hands. The head I did cut off because the mannequin slightly looked to the side and that was lame looking. I re-positioned the head too and viola ... that´s it.
Oh and the fingers: I looked for a mannequin with seperate fingers (many of them have some fingers molded together!) and did cut them off. I used the heavy duty tape too to put them togerther again. I didn´t fiberglas them, because I wanted them to stay flexible.
I now could bend them in form as liked. In my case one hand to hold the blaster´s trigger and one to hold the barrel.
I first thought it would be hard to get this done ... but it is not.
Hope I could help a bit!