We (that is, our interns and my colleagues) also attacked a straightforward/naive hardware implementation in an FPGA (reconfigurable hardware); we/they achieved at least a few centimeters of distance (using the open-loop antenna shown.)
A truly hardened hardware implementation would be very hard to attack. The contribution of this work is mostly in showing that you can break realistic-but-not-great implementations very quickly, cheaply, and without needing to open most enclosures.
The interesting work here is definitely on the measurement/acquisition side. Ultimately if it's an unprotected AES you're going to be able to exploit some leakage given enough measurements.
This is pretty consistent with recent results that attack more 'exotic' targets; the post-acquisition phase uses the same old techniques that were 'discovered' in the very early 2000's. It seems to be that once you've found the things you need to do to get clean measurements you can just use the straightforward linear-dependency related stuff or do a simple profiled attack if that suits.
A truly hardened hardware implementation would be very hard to attack. The contribution of this work is mostly in showing that you can break realistic-but-not-great implementations very quickly, cheaply, and without needing to open most enclosures.