Another interesting siren, the 1000 on Lincoln MS in Denver is Jailbar, but has a Black Chopper Cap, and i think it was a yellow horn with internal black paint (inside of horn). You don't see many sirens like that these days.
Speaking of weird sirens, can't forget about the Naperville Black/Chocolate 2001's along with Bowling Green's Cow-Spotted 2001's.
And again, the Square-Horned 20V2T. I spotted at least 5 out of the 50 that were made. 1 was taken down in Allen, 2 still up around KC in MO, 1 in Russiaville, and 1 that was possibly relocated in Washington, IN.