Development of an Easily Updated News Website

We need the development of an easily updated news-style professional website.
The website will be a satirical comedy website in a similar style to a web-based newspaper offering such as the Times or Telegraph etc..
The most similar site we are aware of is www.theonion.com in terms of content, design and image.
As a news site we will require the design to enable very easy, flexible and regular self-updating from several sources.
The requirement is for a turnkey solution - we provide you with the website address and you provide is with a fully designed and hosted website which can be edited in-house.
It needs to be robust, reliable and have the following features:

- professional aesthetic appearance
- very easy to update by several people from windows-based PCs
- have different sections
- can accomodate news items of differing sizes from one-liner to full-blown article, all with images
- visually strong and pleasing to read
- excellent intuitive navigation
- latest news section
- twitter feed
- logo
-area for advertising
- flexible in terms of number of news items listed
- text and photo uploads
- other features suggested by the developer not listed will be positively received
- logo design
- access to old news stories/archives possible through menu navigation
- strong password protected editing
- legal disclaimer advice
- contact page
- possible sign-up of members to join us
- optimised for search engine ranking