kegentile

This plugin will create a tag cloud for a specific author. This will allow a visitor on your site to drill deep down into an author’s specific content.
It uses all of the same parameters as wp_tag_cloud(), but adds an additional one for the author_id. When the author_id is passed an integer of a published author that has tagged his or her posts, a tag cloud will be generated.
It will also create a new permalink structure on your site of
www.yoursite.com/author/author-slug/tag/tag-slug
***Note: that you must be using any custom permalink structure for this plugin to function. Also, custom taxonomies is currently not functioning with this version, please look forward for this in a later version.

Author Tag Cloud

Creates a template tag to create an author specific tag cloud and creates a new permalink structure to drill down into content by author and tag.

keith_wp

The normal WP Tag Cloud widget only uses one taxonomy at a time, and doesn’t handle the default post_tag or category taxonomies being assigned to custom post types.
With this plugin, you can now configure (on a per-widget basis):
<ul>
<li>which taxonomies and post types are to be included,</li>
<li>the size of the smallest and largest tags (in different font units),</li>
<li>which terms should always be excluded from the cloud,</li>
<li>the maximum number of tags to show in the cloud,</li>
<li>how to order the tags – alphabetically or by number of tagged posts (ascending or descending), or just randomly,</li>
<li>how to treat tags with just one entry – leave alone, remove them or link directly to that post,</li>
<li>whether to make links no-follow,</li>
<li>what case the tags should appear as,</li>
<li>the widget background and tag background/foreground colours,</li>
<li>and how long each widget’s output should be saved for, if at all.</li>
</ul>

Combined Taxonomies Tag Cloud

A widget to make tag clouds out of multiple taxonomies, across multiple post types and control their appearance.

Author Tag Cloud vs Combined Taxonomies Tag Cloud