Noticing that Really Right Stuff (www.reallyrightstuff.com) showed an L Bracket for the X10, and the X20 I asked them if they were going to offer an L Bracket for the X30. This is what they replied:
"Thank you for your email. I have passed along your request to our design team. No final decision has been made on a Fuji X30 specific plate at this time, however if you know of anyone else wanting a plate for this camera, I encourage them to send us an email."
I have bought their SLR L brackets before, and they are very well made. If interested you can contact them here: info@reallyrightstuff.com
While you are waiting for that there is a small base plate for the X30 made, and sold by Acratech. You can order it from this link:
http://www.acratech.net/quick-release-plates/2183/