Common green lasers do not use green diodes, which are still VERY rare.
Green lasers uses DPSS modules, which usually contain diode, crystals, optics and driver, you just add battery to it. They can be bought on many Chinese sites, like o-like.com. As for US sites, sorry, I can't help you.
And hey look ! O-like even sells direct green diodes !
EDIT: And look ! DTR has them too .. gee things run around so fast ..