Social Media Post Engine

Project Description:
We need a mechanism that will allow users on our site to publish a status to the more popular social media sites. This functionality should be very similar to the "YouTube" share functionality. Please see the attached image for an example of the functionality requested. (This is not an exact mockup)

For the purpose of this project the following functionality must be met:
1. The "engine" must open in a "pop-up" window after user selects a "tell my friends" button
a. The "pop-up" may open an iframe if it is the best option
b. The "pop-up" must use pure HTML/CSS mechanism to open/close
2. The status text must include an input based on a session variable input (such as a username)
a. The input is appended to the status (i.e. "Come check me out at {website name} my username is {variable input}"
b. The status input text must also include a link to our website.
(for the purpose of this project please use www.fakewebsitename.com)
3. The "engine" must prefer Facebook as a default
4. The user will be able to select from other social media sites
5. The "engine" should automatically post to the chosen social media site using appropriate API or cookie data
a. If user information is not available allow for user to logon to chosen social media site
6. At a minimum the "engine" MUST support:
a. Facebook (Default)
b. Twitter
c. StumbleUpon
d. Tumblr
e. Google+

The successful project must incorporate the following requirements:
1. All script code must be fully marked-up
2. Scripts must produce HTML5 compliant code
3. All CSS must be CSS2 compliant
4. All CSS must be clearly labelled
5. The "engine" must be cross-browser capable (two major version releases)

The final product must include:
1. All appropriate code (script, CSS, HTML)
2. Any specific usage documentation describing use of variables or "customizations"

IF YOU ARE RESPONDING TO THIS PROJECT PLEASE READ THE FOLLOWING COMPLETELY!!!

We will not provide any source files. All of the requirements must be provided in your scripts or html.

Please provide links to similar work by you or your team for review. If your proposal does not include links to similar items we will not consider your proposal.

Please PM for clarifications or questions.