to discover that is not possible to loop unwarped clips. I keep apart my strictly personal opinion that is a kind of cultural and aestethical violence to force musicians and creative mind into thinking that time must be something like a squared BOX despite his true nature (that sensible ears understand naturally.) 
apart from that:i work also for theater. my music has many (luckily) time and meter changes, but also uses background soundscapes (like forest or city long recordings)
i have tried all the workaround to loop unwarped clips, but no one gives me the opportunity to loop a long soundscape and keep it at the same speed/pitch even if the musical sequences of my live-set do change time.
i beg your help on this question, i hope to have been clear.
Alessandro