Yay. That rattle is annoying as shit.
Everyone does realize that the drive-train DESIGN is responsible for this problem?
The engineer talk that Jeremy Clarkson had with the engineers before he test drove the GT-R in the episode he broke his neck (supposedly) he made mention of it.
The drive-train only lines up perfectly under load. When fully accelerating, the annoying rattle is gone.
But that design wears that bellhousing terribly over time. A lot of design changes have been made to improve it over the revisions to keep the wear down, but with that design there's no way it can be permanently FIXED.
The aftermarket has made some attempts to fix it (including WillAll), but they are fighting the original design. Unless the driveshaft has some redesigned flex points or mounting angles I'm not sure how that can be fully addressed.
On the other hand, there are several first year CBA's around that have the original bellhousing. Mine included. It rattles like hell until it is warmed up and under load, but as long as it doesn't damage the motor (I know it can under certain circumstances) I don't feel compelled to replace the bellhousing yet.