Warning: this effect is extremely processor intensive. It will take a very long time to render! FCPX will be unresponsive during this time, I recommend adding it to your timeline and leaving FCPX to do it's thing for a while (or just open it in Motion).
I put this together to test FCPX's ability to handle 3D. It is about 50 text layers stacked in Z-space, a simple camera move, & blur to simulate shallow DOF.