Not as of today. But it sparked my braincells, it shouldn't be too much of a hassle doing it though.
The main problem is that the AssetLoaders are tied into the notion of getting things from files that are located as resources. I'll put up a task on the TaskBoard for sorting this one out. Basically what you'd need is a way to be able to register your own
FileStreamer that inherits the IFileStreamer and have URI scheme support for FileStreamers.
That way you could create your own FileStreamer that accepted filenames like this: