So you want to use JSFUnit outside the container? The wrapper code relies on knowledge of the JSF component tree, which simplifies the API. So to do this you would need to get all the client ID's for all the components and ship it to the client.
So it's possible, but it can't be done right now.
There is tremendous advantage to in-container tests. Otherwise, you are just doing black box testing, which is much more brittle.
Interesting idea though. Maybe I'll try it at some point.