Limit maximum posts

Is there a way (or could you please add) an option to limit the maximum number of posts? I see your WP_Query is hardcoded with -1. I’d like to be able to set this parameter in the short code so I can (for example) separate out the latest document from the list of all other documents.

If it helps you visualize what I mean, I’m creating a page of newsletters. The newsletters will be uploaded in PDF format so I’d like to link to the most recent newsletter at the top, then include a separate heading/text with a list of all previous newsletters below.

http://wordpress.org/plugins/document-gallery/