c5pro has transposer. That would certainly come in handy to have, but you don't need that for modeling clothes. People model in hex and carrara. I think most would agree hex is better for modeling(certainly more powerful) and I think easier.Silo is liked alot too and would probably also serve your purpose, it has a nice displacement tool that hex doesn't have, tho hex has more features.Some prefer it to hex.Hex works well with carrara. People also use truespace and wings3d. It's personal what a person things about the interface. I would go try the demos. As far as morphs go...not sure about modeling for that. You would need the ability to utilize a none poser format(probably obj). D|S has a plugin, but not sure about poser.

No need to think outside the box....
    Just make it invisible.