Some things to think about... 1. Maybe there's no good reason for the files to be so large; for example, maybe the maps are at an extremely high resolution tha

Some things to think about... 1. Maybe there's no good reason for the files to be so large; for example, maybe the maps are at an extremely high resolution that will never actually be viewable at the original level of detail on an iPad. Should some effort be spent up front to create iPad-sized versions of each page of the PDFs? This type of thing could be automated with the right software, e.g. something that goes from page to page, scales everything down to 30% and writes a new PDF (and you'd want that, so that modified versions could be shrunk in a push-button way). 2. Look at on-the-fly compression/decompression. The device could hold compressed versions of each file that are decompressed on demand by an app. Smaller files would not only allow the device to store potentially everything, but it would make any transfers/syncs that much faster.