There will ultimately be 10 DVDs, plus the movie. 
The first disk of the Rose Collection has 7 eps; 
the second has 6. When you get into the Black 
Rose saga, the episode count drops to 3 or 4 per 
or so. 

http://www.animeondvd.com/reviews/category.php?
category=1&view=5

has titles, release dates, etc. But the set won't 
be completed until November this year; only the 
first seven plus movie are currently available, I 
believe.