A memory scanner for OS X by Joe Savage. The application is still very much a work-in-progress, and at the time of writing is certainly nowhere near a "complete" state.
This project was developed on a Late 2013 Retina Macbook Pro running Yosemite. While I would hope it runs somewhat sensibly in other environments, I can make no guarantees to this effect. The OS X Mach functions and structures seem particularly prone to undocumented changes between OS versions, and I suspect that future versions of OS X will make cross-process memory inspection more and more difficult (I'm looking at you, El Capitan).