Is it possible to push node summaries (teaser text) onto pages other than the "Front Page"? I see the option "Promoted to front page" but is there a workaround for promoting them to sub-pages as well?
"Promoted to front page" can be used as a views filter. So you could create views based on that (so it displays node teasers that have a certain taxonomy and are "Promoted to front page").
Another simple way to mimic "Promoted to front page" is to add a taxonomy select field to your content types, and then the taxonomy pages would display the specified content.
Does this answer your question?
Alternative to mtro's answer (which is correct), I find it also useful to use the "flags" module. http://drupal.org/project/flag
Create a flag like "promote to sub-page" then create a "sub-page" view which selects nodes with that flag.
Besides, you can also use Rules module.
With Rules, you can specify the condition and action on a node is prompted to front.