First thing's first, this idea was partially inspired by [Unabubba]'s "SnowMowChipNBlow" [link].
Near as I can tell, a snowblower works by using an auger to scrape snow toward a central input, and then using a fast-rotating impeller to blow it out the top discharge. One could possibly turn the snowblower into a leaf/yard vacuum by attaching a collection device to the discharge. The two best methods would be either a flexible, porous bag, such as a lawnmower bag, or a long hose for directing the leaves to another location. A snowblower's basic design should make it blow the leaves/grass/trash powerfully enough to direct it through a hose.
A quick search on google yielded confusing results. If anyone thinks this is baked please let me know.-- fogfreak, Jul 24 2003 SnowMowChipNBlow http://www.halfbake...ea/SnowMowChipNBlowPartial Inspiration of This Idea [fogfreak, Oct 21 2004] halfbakery