Yes, that should be possible – it loads JS packages from a custom server right now but there's no reason it can't use Webpack. You'll be able to reload immediately (without recompiling) already by pressing Cmd-R in the simulator.
Re:Use ReactJS to Build Native Apps
by danabramov on Wednesday January 28, 2015 @02:59PM
(#8962170)
Oh that's sooooo great. Thank you.
I dreaded my Xamarin build times..
[1]: http://gaearon.github.io/react-hot-loader/