Limit Post Revisions Network Option Wordpress Plugin - Rating, Reviews, Demo & Download
Plugin Description
A Multisite Network plugin to add Network->Settings to limit, or disable, the number of post revisions and set the post autosave interval.
Notes
I based the default plugin values for the constants AUTOSAVE_INTERVAL and WP_POST_REVISIONS on the discussion here: http://wpmututorials.com/how-to/managing-autosavepost-revisions/