The Federal Signal Legend is a very modular and highly customizable lightbar available in lengths of 24" (Golf carts), 45" (Rear lightbar on a prisoner transport van or suv?), 53", 61" and 70" (Tahoe). Not to mention a large number of customization options in Federal Signal's lightbar configurator.
Agencies that use it:
None that I know of
Red, Blue, White, Amber, and GREEN!!! No purple ;-;