From the new Thunderbird Shadow, Takara Tomy brings us the Thunderbird Shadow model kit!
A little information thanks to wiki.com:
Thunderbird S, with “S” standing for “Shadow”, is a top secret International Rescue aircraft. Coloured black and rarely used, little is known regarding the enigmatic craft, and that is exactly how its pilot, Kayo, would presumably wish for it to stay.
Although considered a Thunderbird, it is not used primarily for rescue missions like the main five, and is instead used for missions dealing with stopping villains and keeping International Rescue secure, much like Lady Penelope in FAB 1.