So is this the diode everyone's using ?

Nope. The diodes we are using are 5.6mm.

Op probably meant the chip, by looking at the specs. I've wondered the same thing, perhaps they packaged it in 5.6 cans specially for the projectors. Unfortunately, this Nichia datasheet is a bit secretive about the guts of the diode. Some LED datasheets will tell you things like where the bond wires should be soldered to, how big the emitting area is, how big the actual die is, etc., which, in light of the recent pics of people's decanned 445nm diodes, would be helpful in identifying the LD die if Nichia had included this information in theirs.