Here's a nice tool/website you can use to compare every aspect of many mainstream servos. It gives you dimensions and torque specs, and other useful info.
www.servodatabase.com
There's probably many servos that will just drop in to your existing servo mounts. Even if they're not exact, its not hard at all to "adjust" the servo mount areas, but it does take a little bit of time. That link I posted should give you something to study and ponder for some replacement servos though. Good luck with it.