Flighty -
To address the question your raise about acro crabs...
I think they probably do breed in our tanks. I often see some of mine full of eggs.. looking ready to burst. But like every other crab,shrimp,small snail.... I assume the majority of the offspring are readily snapped up as available food by corals and fish.
A few years ago when I got into the hobby many people were scraping these crabs OUT of their beautiful acro colonies... thinking they were predators. That never made sense to me, honestly, since most of the colonies they came in on had obviously been thriving in the wild. I always kept mine, and still pick up strays whenever I can.
Like trying to rear every other delicate species, it think would probably take a dedicated tank with no predators, huge acro colonies for them to inhabit as numbers increased, and 'friendly' filtration to raise the larvae. Even then... it seems that acro crabs may keep the worms at bey (as Mike experienced) but not clear the tank of them, which would be the ultimate goal (at least that would be my ultimate goal).
bec