If you've got inverts in your tank, treat them as you do the liverock: During the fallow period, any cysts on the rock, crab-shells, sand, glass, snails, or ... wherever ... should hatch, sending theronts out hunting for fish to infect. When they don't find any fish, they'll die of starvation.
I've heard a lot of tales of failed fallow periods in this thread, but have only my own story to tell. I had ich in a 65 gallon DT - the fish who'd been there a while were OK, but any new fish contracted the disease and died rather quickly, so I made the decision to set up a QT and go fallow. All the fish were treated with chelated copper (I found ionic copper to be rather lethal to the wrasses I love :-( and TTM didn't work well for me) and Prazi-Pro, and returned to the display after about 73 days. (I'd wanted to go 76, but things started going south in the QT...) Although I still get jumpy when I see a white grain of sand or micro-bubble adhering to a fish's slime coat, so far things in my display have been going very well for the last several weeks, and I think I may just have the buggers beat.
During fallow, continue to feed your display as well as your fish - give your bacteria something to nitrify! - and look at what's going on in there! Your corals will glow and grow, your inverts will move confidently without threatening shadows from above ... and your 'pod population will go through the ceiling. That fallow period can be as fascinating (on a smaller, macro scale) as a tankful of brilliant fishes. Ich isn't magic; it's a parasitic creature, and subject to its own biology. You can beat it. Good luck!
~Bruce
