Trevor Green

Adds a custom post type of css that will compile all entries into a single minified css file that will automatically be enqueued to your site.
Minified CSS is stored in a transient for caching.
User now needs ‘edit_themes’ permission to see the css editor. By default this is only the administrator.
<h4>Shortcodes</h4>
Shortcodes are now processed during compilation of your css.
An new shortcode has been added called:
[meta key=”(name of arbitrary custom field)” post_id=”(optional)”]
This allows you to define a whatever custom fields you like on an individual css post and use them in your css.
Ex. a { color: [meta key=”my_color”]; }
So you can define common elements and use them throughout your css.
If you like you can use the option post_id to put those values from another post. So you can have one master css post with your primary colors and such and referance it in other posts.
<h4>Credits</h4>
Minification code from <a href="http://www.lateralcode.com/css-minifier/" rel="nofollow ugc">http://www.lateralcode.com/css-minifier/</a>
<h4>Notes on Function</h4>
All css is compiled on save unless the transient has expired. If which case a query is run to compile the css durning rendering. 
I may add option to use either a wp_option or a transient based upon user preferance.
Css is compiled by menu_order. I would like to add more options for better sorting.
There is an options page that outputs the css into a textarea so that you can review the final css in the dashboard.
Email me to request customizations <a href="mailto:trevor@mailagc.com" rel="nofollow ugc">trevor@mailagc.com</a>
Future options may also include the ability to write your css to your theme directory. This plugin currently must be active to keep the css available.
I’m trying to follow the path of Mark Jaquith. Read more here. 
<a href="http://markjaquith.wordpress.com/2011/06/07/how-to-write-a-plugin-that-ill-use/" rel="nofollow ugc">How to Write a Plugin I’ll use</a>
<a href="http://www.azuregreencreative.com" rel="nofollow ugc"></a>

COP CSS Custom Post Type Lite

Adds a custom post type for implementing theme independent css.

George Pattichis

Simple CPT is a free WordPress plugin that lets you create custom post types and custom taxonomies (eg: categories, tags, etc.) directly from your admin dashboard without writing a single line code.
No more editing files manually. With Simple CPT you can create a new Custom Post Type in less than 1 minute.
This plugin is written using only native functions, included in WordPress core, so it does not in any way reduce the performance of your website and will not cause any compatibility problems. Simple CPT is completely free, it will save you time and it is compatible with almost all themes and plugins out there.
In just a few minutes you can adapt your WordPress site to any type of project in a professional and extremely efficient way, e.g. ecommerce, hotel, restaurant, events, portfolio, community websites etc.

Simple CPT

Simple CPT provides an easy to use interface for registering and managing custom post types and custom taxonomies.

COP CSS Custom Post Type Lite vs Simple CPT