I do agree that you are not going to be able to "cycle" a tank in the traditional since for lack of a filter in a smaller set-up. BUT, I am a firm believer that, if you have a smaller set-up you should have a filter alternative anyway. LIVE PLANTS! They act in the same manner that a filter does in a more natural way. Ammonia becomes nitrites -> bacteria converts them into nitrates -> plants have all kinds of fun eating nitrates and turning them back into all kinds of healthy stuff! In this was a nitrogen cycle does occur and therefore. . . the tank has been "cycled!"
And I always do mine fish in. Something about the plants, but I never get enormous ammonia or nitrite spikes and my fish have never suffered for it. *shrug*