I'm struggling to find a solution for this problem that isn't overkill
or that isn't quite enough for what I'm trying to do..

So here's what I'm trying to do:
Add a column (willing to be a Custom Context Menu link) to a document
library that is sort of a calculated URL. By that I mean I would like
the Link to be automatically filled in pertaining to the Documents Path.

Here's how I'm attempting to use it:
I want a link in a SP Document Library for when the user clicks it, it
would send them and some of the documents information (Document URL &
Document Name) in a querystring to an address outside of sharepoint.
The purpose of this is we are trying to give certain users the ability
to pass the path and names of documents in the library to an outside
application that they will be able to maintain some special notes and
such about the document - without having to rewrite an application in
sharepoint.

I know I would be able to do this by creating a webpart that pretty
much Renders the Document list in my own way.. but we are looking at
doing this for many different document libraries, and want it to
intertwine with the SP's rendering of the list.

I'm aware this isn't a very friendly explanation - I hope it makes
some sense. My main issue is that for a Calculated Field there isn't
simple a value for the Documents Encoded Path?