timgaunt wrote
The client would like to publish articles to the site -some which are publicly accessible, others however will require the user to subscribe to access (i.e. through WorldPay).
You can do this by setting page/module permissions for Registered Users and Unauthenticated/All Users. You can also setup subscription fees for registration and there are various payment gateways available by default.
timgaunt wrote
The client would also like to offer news in the same way, forums and rating systems. Now I know there are modules available/the functionality built in for many of the requirements but what about things like the subscription only articles/news?
You can create your own Security Roles (much like User Groups), place users in them and assign the permission to access the exclusive content. I think User Grouping is the best way to manage access.
timgaunt wrote
Is there a module (or combination of modules) available that takes payment for the account's access or is that something we'd have to develop ourselves?
There is the Store project which you may want to check out. Personally, I'd try to look into the available modules or free 3rd party modules before I start developing. Sometimes, I also refer to SnowCovered.com to see if there are modules worth buying (with source).
timgaunt wrote
Another slightly off tact question is: Can I limit the total space available for the uploaded files?
With the host account, you can assign limits to the disk space, number of pages and number of users a portal can have.
Hope this helps a little. 