Excerpt Length, customize in shortcode feature request

It would be very nice to be able to choose the excerpt length right within the shortcode via
“number of words” or “number of letters”

for example…
excerpt_length-word=”20″
excerpt_length-letters=”100″

[display-posts category=”frontpage” include_excerpt=”true” excerpt_length-word=”20″ display-posts wrapper=”div” posts_per_page=”2″ order=”ASC” orderby=”date”]

http://ww.wp.xz.cn/plugins/list-category-posts/