There is an official announcement for the first Haruhi-chan DVD (with two different versions) on
haruhi.tv.
The running time is of around 51 minutes and not 40 minutes, which means that the DVD can contain the first 10 Haruhi-chan episodes and 5 Churuya-san episodes (as well as the preview video and the opening).
With three DVDs there could be 30 Haruhi-chan and 15 Churuya-san episodes.
ETA: There are also some new
character sketches and an announcement of the second
Churuya-san CD.