How do you install new stuff on your machine without super user rights ? Do you have a specific user to run apt-get ?
About the channel, the (real) install script is based on Fabric and use SSH. So you can refer directly to this: http://cozy.io/host/install.html
Not that what you are suggesting is good in the first place.
1. they can be signed
2. they can be analyzed (also at a later date if you keep them around) to figure out if any "mis-feature" was added after the fact or came from upstream. Those scripts typically download all kinds of other things during the installation.