The original Dreamcast Rip Database is back online! 
Note: I found the original ripdb.dat at http://web.archive.org/ and I converted it to MySQL + PHP. I don’t remember who was the original author of the RipDB website, but I belive that he/she won’t mind that I’ve taken it back online.
In the RipDB you’ll find info on specific DC game rips, how to patch them and if the rip works or not.