This is actually the method that Google recommends for these AJAX powered websites. https://developers.google.com/webmasters/ajax-crawling/

I am just letting people out source the hard work. Since the rendered page will be proxied from BromBone, there will be no way to tell that the same it rendered the file instead of the normal webserver.

That's very useful info; I had no idea. I thought the Google crawlers were basically headless Chrome bots so I wouldn't have expected this.

Do you mention this on your site? Seems like a good endorsement, "This is the correct way to get indexed, as per Google!"

I have a section about that. I hope people will read it.