High Rich,
Am I right in assuming that you are asking if I will run node.js on iOS so that you can serve your tiddlywiki rather than opening it as an .html files?
If so the answer "most likely not". I've considered it often, and experimented with an alternative approach reading and writing folders of .tid files etc, but never quite got to the point of satisfaction where I was willing to ruggedize and release the code.
Meanwhile, earlier this year Jeremy launched a discussion and a prototype concerning a dedicated node.js based TiddlyWiki solution for iOS.
If he proceeds with this development then I expect it will be the best way to go for what I think you are looking for.
Cheers - Chris.