Rails 4:- I know it's not in full release yet but by the time the project is finished Rails 4 will no longer be edge. I would like to take advantage of the new live streaming capabilities. Plus it may give us a chane to put something back into the Rails project with any feedback we may come up with.
It would be good to create this project as a gem or rails engine. If anyone has experience on how to approach this then please speak up.

Server:- A server will have to be chosen as Unicorn (my personal favourite) apparently can't handle live streaming although willing to be corrected on that. but nginx I think is a must, again willing to be convinced otherwise
Any suggestions?

Authentication:- For more control we should roll out our own authentication rather than using an authentication gem.

Github:- Github is the obvious place for hosting the source code.

Testing:- Full test suite will be needed. RSpec, Capybara and Factory Girl are my favoured options but again, willing to be persuaded otherwise.

That's about it for the moment, Please feel free to respond wioth offers of help, advice suggestions etc...