Although performance is important, as someone who does PhoneGap apps for a living (http://mulberry.toura.com) I can tell you that there are so many other performance problems with HTML5 that this is wayyy premature optimization.
11ms isn't going to kill you, and if you are experiencing performance problems, there are far more important things to do (check for DOM leaks, dealing with 3G latency, etc.) than shave off a few ms on a call to a native function.
Or put another way, there's no reason to create another PhoneGap-like framework to save 11ms on a native function call. There are a whole lot of other reasons (many business-related) of course. But this isn't one of them. :)
Thanks,
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Matt