[ordinaryman]

I am working on such an app over Google App Engine, iFreeTools Creator : http://creator.ifreetools.com

Requires nothing more than a Google/Google-Apps user account to get going.

You can define Entities ("table"/"sheets") and Attributes ("columns"/"fields") to get working with your database app within a few minutes.

Integrates with Google Contacts (import/upload), Google Docs (attach docs to database records), Google Maps (mark and search for records based on geographic location). Google Calendar (export events/tasks-like data) and email integration are coming up later.

The web-app can be mapped to your own domain like http://app.yourdomain.com (using Google Apps).

Other features include :

  - Authorization Profiles for fine grain access control up to field level.
  - Custom Views to filter data matching your criteria.
  - Custom Actions for single click edits.
  - Automated Audit of all write operations
  - Bulk Export & Import of data as CSV files.
  - Support for drop-down choices, 
      look-up fields (references) and 
      image fields (with auto thumbnails for list view)
  ..and more.

Hope you like it. Feedback welcome.