I just purchased a new MacBook Pro 13" plus a new Thunderbolt Display. To finish up my new set-up, I also ordered a Logitech wired laser mouse and the beautiful, backlit Moshi Luna... both to plug-in to the back of my Thunderbolt's USBs. Within moments I noticed that the Luna started "flickering," and suddenly went black, and I lost all ability to use the keyboard. The mouse worked fine, but when I tried typing into a document or on a website on the keyboard, I couldn't create any characters.
After switching the USB ports and temporarily bringing the Moshi Luna back to life, it would again flicker and go dark.
This prompted me to call Apple to find out if I needed to make any adjustments to my keyboard set-up. The customer service rep said he was unaware of any issues with the Moshi Luna, and while he put me on hold to find out additional information, I plugged the Luna into one of the MBP's side USB ports. It worked perfectly, and by the time the rep returned to the phone, I had replugged the Luna back into my Thunderbolt. This brought the keyboard back to life, and for the duration of our phone call (about 10 minutes), the Luna continued to function properly.
I also visited the Moshi site to see if there were any additional set-up instructions for a Thunderbolt Display, but was unable to find any relevant information. So I sent them an email and explained my problem.
I started using the Moshi Luna again today for a work project, and sure enough, it flickered and failed again. Since consolidating all of the wires I used to plug in to my old MacBook Pro when it was connected to a Cinema Display and only having one wire go into my MBP, I decided to get rid of the Moshi Luna and go back to a more traditional keyboard.
So I visited my local Apple store today, returned the Luna, and purchased an Apple Numeric keyboard, which appears to be working fine with the Thunderbolt connection.
When I returned home and after I set-up the new Apple keyboard, I received an email response to my question from Moshi, which referred me to this "Thunderbolt" discussion forum on the Apple site.
I would avoid the Moshi Luna if you happen to use a Thunderbolt display for your MacBook Pro, since based on my limited experience, their "USB technology" seems incompatible with Thunberbolt.