http://en.wikipedia.org/wiki/T-50_tank
T-50 was light tank and intended to replace the numerous T-26. There were produced 69 pcs. Mostly, because of the very deficit engine V-4, which went directly for T-34 production.
Only tanks with vehicle engine had a life: T-60, T-70 and SU-76.
Would be nice to have such tank in SF, but the small quantity and a very narrowed area of using (only near Leningrad) makes appearance of this tank with a very doubtful value.