I have been using a Sceery Cottontail (AP-6?) and a Primos Jackrabbit call for 20+ years, along with my very first call from the late 60's by Weems.
They all work great, but I do have a hankering for a more custom-type call.
Take a look at Carver Predator Calls, RRcalls.com or just go to Predator Masters and look over the sponsors.