Just a thought:

Couldn't you just host the releases on Github using the release function? Just tag the releases and then upload the corresponding binaries for that release and tell people to download the binaries from there.

Also, github pages could be utilized to set up a website for the open source project. A project site could be set up using github pages and it would all be hosted by github for free. In announcements text file could be kept there and armory could pull the announcement from there.

If we go with that option, I could help as I have experience with setting up all of that stuff for github, although when it comes to web design and development you will need to get other people to help. Thankfully the github pages thing actually makes making a website there really easy.