Quite true, there are a large number of clips on Limewire, and the ones that show up in a search are generally immediately available.
It takes a while longer to download popular clips on e-Mule because of the distributed nature of their network, but there literally thousands of clips on there. (You have to use some creative search terms to find them all, because most dervers cap your search results at about 200-300) Many of them are rare or unique clips that I haven't seen anywhere else.