WORDPRESS PLUGIN with cross-site messaging and widget(s)

We need a wordpress plugin, initially very simple, to integrate our micropayments solution and provide a 'tibjar' to collect microdonations for wordpress users. We expect this job to take a day or two for someone with the right experience. Please include in your application whatever you feel will best allow us to have confidence in your ability to meet our requirement. At the very least, a link to a live demonstration of a wordpress plugin you have previously developed is required. WIDGET DISPLAY ELEMENTS 1. Blurb: Text specified by the wordpress plugin user asking for 'tibs' (our term for microdonations) 2. tib button: for the viewer to click on that will open and display a tibdit webpage, in a popup window (unless blocked). 3. testmode indicator: An icon that is shown if the bitcoin payment address is a 'testnet' address. 4. Counter: A count of the number of tibs sent to the combination of bitcoin address and sub-reference. The sub-reference will typically be the wordpress post ID. 5. Thank you message: this configurable text is displayed to the viewer after a tib is confirmed. It can replace the tib button, which should be disabled after a tib is sent. LOGIC ELEMENTS 1) payment address and sub-reference validation: The plugin needs to verify that the payment bitcoin address is valid, determine if it is a testnet or mainnet address, and check the sub-reference (if any) conforms with tibdit URL requirements. 2) opening the tibdit window in a pop-up: A tibdit URL needs to be constructed that includes the bitcoin payment address, and a sub-reference. 3) postMessage listener, and popup window closure monitoring: when the viewer confirms payment of a tib in the tibdit popup window, a packet of data (the 'proof-of-tib token') is sent via postMessage to the plugin. No AJAX or other cross-site technology is expected to be needed. 4) cookie to record tibs paid by viewer: If the post/sub-reference has already (or just) been tibbed, the reader should see a thank you message and not be able to re-tib. This should have a timeout, configurable by the plugin user, but with a minimum of 24 hours. 5) Counter persistence: the packet sent by tibdit includes the total number of tibs sent to this bitcoin address and sub-reference (post ID). This needs to be stored persistently, and the stored number used to display the count in the widget. EXTRAS AND NOTES The appearance of the text elements etc should reflect the site style. tib button and testmode graphics will be provided by tibdit. postMessage is not supported at all by some legacy browsers, [and is still essentially borked on IE 11] so browser and browser-version detection will be necessary to either prevent widget/button display, or display a message in-place of the button for these browsers. As an alternative to the widget, a button that can be placed at the foot of a post is needed. This button should also display the counter, and be disabled and/or replaced with a short thanks message after the viewer has tibbed. Where the widget is not associated to a specific post or other object with a unique ID, the sub-reference should be configurable by the plugin user. The sub-reference can also be left empty when the micro-donation is not related to specific content, but simply to the wordpress user or their site. While bitcoin may be of interest, no knowledge of bitcoin is required. We can provide links to the necessary bitcoin address validation code or library. FOLLOW ON WORK We intend to expand plugin functionality in the coming weeks and months. We want to enable tibbing micro-payments to unlock additional 'below-the-fold' content. We will implement workarounds for non-conformant, broken browsers like Microsoft IE where possible. Further enhancements to the plugin will be needed as we extend tibdit functionality. However for this initial plugin development, the emphasis is on keeping it SIMPLE, and quick delivery of the finished plugin.