In the DVDreview film vault, you can search by studio... But I don't think the list is very updated, at least some of the newest releases aren't included... http://www.dvdreview.com/movies/FilmVault.html
However, I would be very interested in a site where you could search even more specific, like: DTS titles by New Line for example...
Keep the suggestions coming!
Go to Link Removed, click on the link to "Advanced Search" in the upper right, and in the form you can leave the "title" and other fields blank, but you can choose the Studio via the pull-down menu list about 2/3's of the way down the left column, if I recall it's placement right. Choose your studio, hit [Submit Query], and there ya' go!