Hmmm...maybe you could pop his head off and break out the hot glue gun? This is what I have to do when re-rooting customs myself. I really want that little Pinhead though, so hope you can recreate him..or at least figure out those pins and make a tutorial for it.
Yeah, I see what you mean. The plastic is a bit harder then on the older G3s, but then again I haven't tied custommizing a G3.5 yet. >.>; Have you shared your customs in MLPArena? You've got some great designs for customs and I see you scaring some of the members there.