RF, that would be a pretty nice pose. I too am looking at that kit, but not for a little while. If you look back at my previous figure builds you'll see that I'm not really one to build something OOB. The best thing that I can tell you for modding figures is to drill out holes and attach everything with wire. This gives your figure's joints strength and helps in changing the pose.
The challenge that I see when modding this kit is that he's not wearing clothing. What I mean is that you can't add in folds with putty, etc. You also can't add in additional armor pieces, well you can, but not if you want to be accurate to the suti of armor from the film. My suggestion for this would be to watch the movie a couple of times IOT get a REALLY good idea of what the suit looks like from different angles and what the joints look like when IM moves. I think that this is the best method to getting the research info that you need.
But I'd wait to do all of that until after you have the kit. That way you can look at it and make notes at the same time.
Check out the Sci-fi forum as Swanny is in the middle of building this one up. Modding will be difficult on all aspects since the paint job has to be so perfect. Getting that smooth, smooth surface after all those mods will be hard, but not impossible.
HTH...