I think a chain would be the way to go. Also, I thought there was a motorcycle specific company that sold what looked like an eyebolt that you put in concrete so you can run your cable through the eyebolt, and then though your bike. At least that way they just couldn't pick it up, or roll it.
https://www.kryptonitelock.com/produ...1000&scid=1001
https://www.kryptonitelock.com/Produ....aspx?cid=1003 That looks like the what I was talking about at the bottom, you would jsut have to drill for anchors.
There are some examples of whats out there. Kryptonite is one that I've seen around
Edited after BTB schooled me on chains.