Even if a T4i comes out, the 60D will probably still outmatch it in AF. AF on any XXD is a step up from any of the Rebel series. The 60D was our first "real" DSLR, and it's amazing. The 7D just trumps it in AF.
Buy a 60D used now, and you're more than likely not going to lose much, even if a 70D comes out.