2002 Mazda Cosmo 21 Concept
The Mazda Cosmo 21 is a concept car that debuted at the 2002 Tokyo Auto Salon. It was based in the chasis of a Mazda MX-5 Miata and had the engine of a RX-8. Extensive new bodywork made the vehicle look like the original Cosmo, although the proportions were different due to the Miata chasis.
It is believed that it was built by "Mazda Sangyo" which seems to be a subsiduary company that does engineering work, ambulance conversions etc.
Suspicion is that the "21" means 21st century, because it isn't the 21st anniversary of the original Cosmo. (but, it is not known exactly why they picked 21).
(source: Craig's Rotary Page)