Hi Dave,
Yup what you suggested can work. ETP centrally works with package_id. Rather than making a new instance of ETP just make a new instance of the content folder and use the package id of the package you want to use in cr_folder.package_id. In your case the acs-subsite.
The problem should arise only in theory is the name collision of the content item. For example say the package you picked is bboard. On the bboard you have 2 contents that you want etp to manage. The names of those 2 contents must be unique in cr_folders AND www of the package. This is why etp-* convention is made.
In the CMS that I am working on I did not decide to use this in favor of waiting for using the new portal code, or whatever other features of OpenACS may have. I decided not to use package_id unlike ETP, but there are drawbacks too.
Maybe its a good topic for the OpenACS chat is how to make 2 or more package be accessible on a single site node? Or maybe if this is a good thing to do or not. The purpose of having portlets is to answer this situation, right? I do not know about portlets so I can't comment on that.
