Don't quite get the hang of this.
I'd say the best way to promote it is to build a site with it and show what it can do.
If you're going to give away "sample" versions, you want a "contact point" site to link to.
But I don't understand why you want to "sell" it as a concept. If it is a nice piece of work, you would be more likely to make money by using it to build sites for end users.
If it is neat and light on resources, it is easy to point out to the end user that it keeps the running costs down by a couple of dollars a month. That is a big selling point which does not take much to understand.
There are lots of people on the web trying to sell templates. Truth is, if one can understand enough code to use a template, one copies the concepts and builds one's own template.