I'm using long polling in our application and I don't see that one connection per server restriction here.
I did however see that safari was not leaving the loading state (and thus not firing any of the loaded events, nor hiding the URL bar) if I started the long polling connection before the page was fully loaded.
Once I moved opening the connection to a setTimeout callback inside the onLoad handler (so not DOM ready, but actual load), this went away and the page works normally.
Now this makes sense. As I said below, it seems really strange that this would go unnoticed, especially since one-connection-per-domain affects all sites and not just ones doing long polling.
I did however see that safari was not leaving the loading state (and thus not firing any of the loaded events, nor hiding the URL bar) if I started the long polling connection before the page was fully loaded.
Once I moved opening the connection to a setTimeout callback inside the onLoad handler (so not DOM ready, but actual load), this went away and the page works normally.