This keeps an odd tradition of Thundercracker toys being exclusives, which we previously saw in the Studio Series line from Hasbro and in the Arms Micron line from Takara.
This also continues the trend of Toysrus hosting exclusives toys from Transformers cartoon shows, which they did with RID, and since there are no Toysrus stores in the US it is unknown how that toys will be made available in that country. While it is not the case yet for Transformers, there have been a few Hasbro exclusives for the Star Wars line that have only been made available at Toysrus stores elsewhere in the world with no distribution channel in the US.
If you find it in any store, let us know. This particular sighting was found by Singapore-based TFW2005 user lake88.