iTerm2 build 2.1.4 on OS X 10.11.4 has that capability built in:
View > Tab Colour:
Clicking one of the colours has the following result (Inactive):
(Active)
iTerm2 build 2.1.4 on OS X 10.11.4 has that capability built in:
View > Tab Colour:
Clicking one of the colours has the following result (Inactive):
(Active)