Scope of Effort: Digital Paper Trail SW - repost

I am looking for estimates as to the scope of work required to build a Mac application that would collect information from differing sources and file types (emails, calendar appointments, MS Office files, etc.) in order to build a single, chronological digital paper trail around a topic. Here is an example that gave me this idea: Nine months prior to an important deadline, I began to raise the issue that a critical requirement was not yet in place. I received no direct response, and the few that I did get simply deferred the issue to some unidentified point in the future. Over the next months, I tried repeatedly to explain in detail that not having the requirement in place would be an absolute stonewall. Roughly a month before the deadline, of course, the very people I had tried to warn begin freaking out and trying to blame me for the mess I attempted to avoid. I had a huge amount of information to be able to refute their claims, but I had to print it out and manually sort it. If I wanted to go back to any single point I would have to dig around for the original version of whatever I printed. Maybe a way to design this would be to build a directory that would point to each individual piece of 'evidence?' That way, files aren't moved around to odd places, and they can also be used in multiple ways. The project, at this very early stage, is just to come up with a conceptual software product (including how it would function), and to provide an estimate as to the scope of work that would be required to actually make it. Thanks!