Tyler Tork

Like blog posts, a Page can have an “Excerpt” field to override the automatic excerpt of 55 words from the beginning of the content. However, many themes don’t display this field when editing pages, so you can’t edit it.
This extremely simple plugin forces page excerpt capability “on”. The Page excerpt is visible in internal search results and “Query Loop” blocks, as well as in the output of many plugins (e.g. CC Child Pages). So I generally do want to decide for myself whether to accept the default excerpt.

Torknado Page Excerpt

Pages, like Posts, can have an Excerpt field to override the automatic "first 55 words" excerpt. However, many themes don't enable edit …

Marcus Downing

Zaybiz

A simple plugin to enhance your use of the_excerpt() function. Allows you to change the default title and description of the excerpt box, add an excerpt box to pages and show a customizable jQuery character counter with the ability to limit the amount of characters.
The jQuery character counter from <a href="http://tomdeater.com/" rel="nofollow ugc">Tom Deater</a> provides a user friendly way to limit the amount of characters while writing.

Excerpt Tools

Change the default text and description of the excerpt box, add an excerpt box to pages and show a jQuery character counter and limiter.

Torknado Page Excerpt vs Excerpt Tools