We do have a timeline for development on github.
I'm confident that these tasks will be completed and from the work undertaken so far that we have made good progress. However, these timescales are not set in stone and there will be some movement as we graple with individual tasks.
I intend to use this new STACK code in the autumn of 2011, as does the Physics department here in Birmingham. We will also aim to undertake live tests with a pilot group of students later in August.
I will post updates as soon as we have a public git repository which is stable enough for public viewing and comment.
Thank you for your interest,