If we're talking just SVG, it could be done as a one-time inlining that uses <defs> to define shapes, that get pulled into the page later with <use>. The defs are page-wide and work across <svg> elements. That would fix the duplication, though not necessarily caching on its own with GP's include.
You could put something like this in your markup
And the web server would apply it and inline the contents. It had a bunch of other directives, but this was the good one.