I put together a proof of concept today. Seems doable (and am indeed using the same [list[$:/StoryList]] filter suggested by @TW_Tones above in a list widget to loop through the generation of the fused output).
Will refine and do some minor refactoring (the code is a mess, but I probably can’t tackle more meaningful changes at this time). I did find a trivial bug investigating this though, when selecting raw HTML output. Released the bugfix just now. I am surprised this didn’t surface earlier.
I am probably going to add an optional page icon when wanting to fuse the full story list. If that is not likely an approach that works for you, please circle back here.
Also need to confirm you only want open Stream parent tiddlers (and nodes) to be fused, vs all open tiddlers? Easy filter tweak to [list[$:/StoryList]has[stream-list]]…