The SanDisk Ultra Fit USB 3.0 Flash Drive got to be the smallest USB 3.0 flash drive that I have seen! It is about the size of a Singapore 20 cents coin and is capable of a read speed of up to 130MB/s.
Launched on the 19th August 2014, it is retailing for 16GB (S$13.90), 32GB (S$25.90) and 64GB (S$52.90).