technically, each bottle or keg is itself a secondary. All its doing is clearing and aging, the vessel is not important. Therefore you should, in time, get just as clear beer as with a proper secondary. I've done a super light summer ale in primary only, and by the time they were drinkable, they were crystal clear. But, some yeast stay in suspension longer by nature, the above beer was a dry yeast and they tend to settle out quick and thoroughly.
I have a question on this topic: Some say that with the prolonged primary, the yeast are still cleaning up ferm. flavors and such. Wouldn't this still occur in the secondary? there is still much yeast in suspension, enough to form another cake in the secondary. I would also assume that the cleaning up of flavors is happening throughout the wort by the suspended yeast, not just near the cake. I haven't read anything along these lines in the recent "2ndary or no 2ndary" threads, and have been wondering about it much lately.