yep, for this scene with all those little water particles, I guess you would need numbers of photons messiah simply can’t produce without crashing. They work best for “glass sphere on floor” scenes, everything more complex is asking for trouble. 
You also have to balance the light intensity, light size, photon amount and photon intensity to get the brightness right…
As far as ZBornToy goes: IMO it is just that, a toy (even if a very cool one) looking for an application. Since you can’t have objects behind objects in a depth map based approach, you are very limited in practice. I created some cool eyecandy with the demo but can’t imagine using it for anything but very “specific” projects.
But yes, the caustics are close to perfect…
Here is one of my tests with it (Quicktime 7):
ZBornToy_Test
As for Motionblur: the new Motionblur options in AfterEffects 7 should be able to deal with something like your scene. It actually analyzes pixel motion, not just frame-blends. Works great in some cases but not in others. Give it a try.
Cheers,