Where can I get highly technical documentation of Macintosh hardware?
As far as repair of hardware http://ifixit.com is actually pretty awesome, more visual than you may be looking for however.
Global Service Exchange might be what you're looking for - its the worldwide system that provides repair manuals, software, and case histories for all Apple products. You might also want to review this Apple page.
If you're a JAMF Casper site and have a GSX account, you can automatically import and track Mac warranty information, which is really useful for larger installations.