Online iOS / Android App Builder

I would like to build an online app builder for iOS / Android using drupal & phonegap. There already exists a drupal module for the integration and I would like to build on this.

This allows users to build apps through a website which then generates native code ready for submission to various app stores / markets

Examples can be found at appmakr.com, genwi.com, swebapps.com

The UX will be as follows:

The user creates an account and using a drag and drop interface can add:

A splash image
A background image
Buttons to the main activity interface
Activities linked to those buttons
Content within those activities
User addable functions

The content types we allow are:

Vouchers (sent via push)
Images
RSS feeds
Text
Video

Additional user addable functions includes:

-click to call
-Social media direct links (facebook likes, G+1's, etc)
-Ability to build stream of randomised content based on accelerometer movement
-Geolocation facilities. Allow app to provide directions to user defined location
-Push notifications. Users will be able to send push notifications to app. There will be a daily limit.

User will be able to drag and drop the UI elements and once they have added content, they will be sent to a confirmation / preview screen.

Once they accept the final app image this is packaged and the site admin will be notified that a new app has been built and needs packaging for app store / market submission

REQUIREMENTS:
Drag and drop basic interface (ajax)
Detailed tech spec on how code conversion process from webapp to native code works and frameworks used (titanium / phonegap)
Code conversion create clean code that does not require adaptation.
App framework must meet OS specification - IE. Android / iOS design guidelines

Website and app design templates will also be provided

If you have experience in this type of project feel free to make recommendations :)