We have included a 404 widget (from Google) to the 404 handler (only serving pages inside www.sjsu.edu).  The 404 widget suggests close matches or alternate links.

Below is a case study for a broken link.

A. URL to an invalid link

B.  404 widget in action

404widget

C.  New search results

Search Results

This is an excellent tools in early stages of development.  What do you think ?.

Cheers,
Harish