Paula, this is a nice idea. To get into the specifics a bit, I would try not to describe GLAM-Wiki as an "initiative" in a talk page banner. I am of the opinion that if we want to seem as inviting as we can to the Wikipedians who will be seeing these project templates, that means using the language of normal WikiProjects.
I would be happy if all GLAM-related project templates looked like the WikiProject United States, like the one here: <
http://en.wikipedia.org/wiki/Talk:Arizona>. Arizona being a sort of sub-WikiProject under United States, the templates all look like "WikiProject United States / Arizona" and use language like "This article is within the scope of WikiProject United States...[description]" at the top, and then below have the specific project, in the case "This article is supported by WikiProject Arizona." Replace "United States" with GLAM and "Arizona" with the specific GLAM in question, like George Washington University Libraries for an idea of how this would look, and how it would incorporate both logos.
Dominic