While I don't necessarily know that anything will be a 'zombie apocalips' I am in the middle of a script for a zombie movie that forced me to research how the rabies virus could be adapted and weaponized. So I know that it's imminently possible, if highly improbable.

My problem with weaponized rabies is that it would be impossible to contain once released. To many mammals are susceptible to it, and it can on occasion be spread by non-mammals as carriers. That makes it rather implausible as a weapon, unless you never plan to occupy the area you just cleared with it. Rabies doesn't burn out. It just keeps coming back over and over again (they even still get rare cases of it in GB, even though it has been all but wiped out on the island).

Just my two cents on the zombie apocalyps idea. I can always be wrong. I've been wrong before.