For those that don't know KaKaRoTo, he was the first person to release CFW for the PS3. And he just said via Twitter that he has a 3.73 CFW working, but not release ready. One special thing about this CFW though, is that he disallowed Backup Mangers (Aka: No backups or piracy.), you still will be able to play all your favorite homebrew on it.
He has also answered a number of questions people asked him in his blog as well