Well, the big ball 'O duct tape that is my hacks on symbolstore.py are complete for now - here is the patch. This project will be carried on in the next term at which point I hope to address some of the current issues, namely - manipulating the directory structure, cleaning up the python code and assembling a unified documentation page.
For now - you may test out the fruits of my labour by downloading this installer of Firefox 3.0b2pre which will install Minefield in your Program Files/Minefield directory (you have no choice for installation dir.) and then copying these symbols into the folder where your Visual Studio (or Windbg) is looking for debug symbols.
The last thing you have to do in order for this to work is to put a path to cvs.exe in your PATH - I personally pointed it to the mozilla-build/mysys/bin/cvs.exe but if you like you can download cvs.exe and put it wherever you want.
Now that you have all you need, open up your debugger (VS or Windbg), attach it to the Minefield process and go!
It will ask you about the cvs calls that gather up the source code, say "OK" or "Run" or whatever is positive. The file should download into the proper /mozilla/whatever structure - on my computer it goes into Program Files/Microsoft Visual Studio 8/Common7/IDE/mozilla/...
That will be a focus in the next round, is manipulating the cvs command so that the source files go to a c:/temp or something. The debugger will automatically want to look for the path that the source file originally came from (in this case, my c:/ff_clean/mozilla/...) - you will have to point your debugger to the correct file the first time and then after that it knows to look in the mozilla folder you selected.
It works for now like what it is; a ball of duct tape that allows you to get the right source code for where you are in the browser without having a build on your computer.
I look forward to feedback about how this works for you, if you use it and if you have any problems arise.