Here is an incredible option:
http://www.rme-audio.de/english/hdsp/hdsp9632.htm
Take a look at the info on that page and see where you can add on modules that will allow for multiple outputs.
I'm currently looking heavily into this option.
Also, all of the cards in the Audiotrack lineup appear to be good options for people on this board. Might as well link entirely to their site.
Also, for the benefit of those who are willing to spend the money to get good, very high quality cards, be sure to post them up, even if they seem to be out of your price range.
EDIT:
PS: one thing I've found incredibly helpful is to link to the page on the manufacturers web site for the particular product. It makes research a lot easier.