Ninja Kick: WordPress Contact Form is a premium plugin that uses different approach for contact forms: it adds hidden form with push/sliding revealing animation on every page of your site. For example you can make menu item ‘Contact Me’ open contact form on the same page impoving user experience (Guide).
Plugin uses modern CSS3 transitions, has layout responsive to screen size changes, works well on mobile devices and reacts on swipe gestures. Please, give a try to how it works and looks on WordPress Contact Form Live Demo Page. Kick your site!
If you’re looking for more universal WordPress solution of sliding panel with same off-canvas effect take a look at another plugin from series — Ninja Kick: Sliding Panel for WordPress.