Maybe we are going about this the wrong way. There are a couple of dozen rigging systems out there that technically supercede the current boning rig that Poser uses. but the added spinal joints aren't a function of a new rig; that is actually the modeller's task, as they are the ones who arrange the mesh sections. Boning in Poser has to take that into account. Perhaps what we need to do is actually look at just how far we can shove the current rig forward. One model with the added torso flexibility. Once that particular part of the figure is tinkered into solid function, move onto the next problem area. This could be kept 'in the family' during development, and presented as a show piece once completed. If the current rig proves itself sufficient for the actual =armature= functionality, then it may be that we need to actually focus on other areas. Say perhaps advancing the boning to more of a 'woody' type armature, and actually developing a method of skinning the armature so that a secondary boning system articulated 'muscle' structures. Similar to JCM, but built in as a true function, not a hack. Or a redefinition of what a 'joint' actually is. Not so much throwing the baby out with the bathwater, but seeing if maybe there actually -is- a better fix than nuking the system