If it's plastic, they're discussing a hot salt method for "adjusting" model poses on BoLS. Basically you heat up a container of salt, stick your plastic mini in, wait till pliable, remove and reposition arm/leg/whatever, dunk in cold water to reset mini, salt disolves away, *magic*
I'm not sure if it will work on a model of that size though, but then again Eldar are kind of spindly.
Only problem with heating and bending the model is that you are not creating a different pose just bending another one to something close. It will look like and bent model most likely. Cutting repositioning, green stuff and patience are your alllies in this endeavour.
Current Project 11/07/10 - Painting Secret Project "Tank 2" Next project: Painting Secret Project "Tanks 3+4" Recently Completed: Painted Secret Project "Tank 1" and assembled "Infantry"
I would do what crc said: cut every joint and then put pins in all the various parts and then glue them together. Then pose him, and then put the gs in all the joints, voila!
Also, you will have to put a joint in his stomach to do that pose.