BenefitsLink has compiled a handy web page with hypertext links to Form 5500 (and its variants) and Schedules, including Instructions, back to the first year the form was required by ERISA.
http://benefitslink.com/src/misc/form-5500-for-previous-years.html
Sometimes it's necessary to refile an earlier year's form, so the web page might be a convenient way to pull up the needed PDF documents, and to see which schedules were required for a particular year.
If you see any opportunities for improvements to the page, please let me know. Thanks!