saving phish/spam email is already done by xComplaint in "forwarded.txt" local file, so it is easy.
Saving web pages is little difficult, but xComplaint from last version download the web pages to look for redirection link, and so it is not so difficult to save also these data.
As now I use 'wget' to download web pages as xComplaint is a CLI application, but with the GUI version I can use WebKithttp://en.wikipedia.org/wiki/WebKit
that seems faster then Gecko (Mozilla engine).
The difficulties come from recovering all other informations, space to save all the web sites, and a form of protection against alterations (I can't imagine a valid one)
I do not know the story behind PIRT and Castlecops (I'm interested in), but I know that the only software that survive to time is opensource.
Imagine an author, lot of work to write an application, keeping it closed source. Time passes, interest changes. The author become not interested in further developing or simply miss time. All the good work is lost. I remember tens of applications disappeared so. And many others released as opensource as they can survive.
GPL software can be further developed from other people. Imagine a collaborative work, we can reach objectives that one men alone can't.
This is the trick behind GNU and Linux, collaborative work, shared intelligence and opensource. They often arrive later, but do it better and forever.