Funny how the X-E1 thread is basically dead but the X-Pro 1 one is thriving.....
Anyway, after several emails back and forth I finally have a SunwayPhoto L grip for the X-E1. And it's pretty nice. Battery and card can be removed and it works with all the arca style bits I have. Including an Arca head
However, the grip blocks the focus assist light

Sunway are aware of this and are redesigning to avoid it. However, the grip is in 3 pieces so you can use it as an L plate without the grip or use the whole thing but sacrifice the focus light.
There are a small number of these "faulty" grips available for £20 each. When they have stock of the fixed ones they will be £44.99. Contact the UK dealer if you're interested
http://sunwayfoto.co.uk/