(sorry for the late reply - didn't see your post)
I would of thought, judging by internet research, that history.pushState or the older location.hash are viable.
Have tried to implement history.pushState on a modern browser against:
(in http://4nf.org/n.js - I'll set my approach live now for evaluation)
It didn't work because control seemed to be completely handed over to the redirected page. It seemed that the browser didn't even get to interpret pushState. I followed the directions for setting up pushState rather carefully... (basically one could see the redirected URL in the address bar)
Do you think it should work nevertheless? Have you any example of pushState in action somewhere?
Thanks a million and kind regards