Dominos is an action bar addon intended to do the following:

• Reuse as much standard blizzard action button code as possible.
• Contain a relatively minimal feature set
• Be easy to use
• Be stable

It includes the following features:

• 10 action bars, pet, class, menu, and bag bars. Each one has customizable settings for padding, spacing, columns, scale, and opacity.
• Customizable paging. You can switch pages on: action bar pages, modifier keys, forms, and targeting.
• Customizable show states. You can tell your bar under which macro options to show.
• Fading bars. You can set your bars to fade out to a certain opacity when not moused over.
• The ability to customize showing empty buttons or not
• Full button facade support
• Keybound support
• Sticky frames
• The ability to move buttons in combat
• A movable casting bar (optional)
• A movable roll frame (optional)
• A movable xp/reputation bar (optional)
• Configurable right click targeting
• Configurable self cast key settings
• Possess bar support

...and will probably not end up with the following:

• A stats bar
• A minimap bar
• True variable length bars

Here's how you use it:

• To see the current list of slash commands, type /dom ? or /dominos ?
• To open up the options menu, either go into interface options, or type /dom
• To move bars around, either go into the options menu and press the "Enter Config Mode" button, or type /dom config
• To bind keys, enter binding mode via /kb or /keybound, or press the "Enter Binding Mode" button in the options menu.

You can find help in the wiki

And source code on GitHub