You can use the attempts described in Louis's post here, but they have limited success.
As of now, there is no way to change the Touchless Control hotword to anything you want, but as per the "hack" you requested, using AutoVoice with Tasker would be the way to go. You can set up AutoVoice to listen continuously for any hotword you want, then use that hotword through tasker to trigger Google Now. A tutorial for the setup can be found here that also uses AutoShare.
Be aware that this workaround won't give voice responses, as it essentially records your voice and uses the input to do a text search. If I find a more usable example, I'll share it here, but this may be as good as can be done without root.