Dungeons and Dragons, the Vampire template can be added to any living race that doesn't specifically have an immunity (such as werewolves). Meaning anything can and has been a vampire at least once in DnD. It can lead to some VERY over powering characters because they keep their old race's benefits plus the vampire abilities. Adding a demon/devil template on top of that is just insane, but perfectly within the rules. (Don't go within 100 miles of a church though xD)
That being said, I still don't agree with this. DnD's Vampire isn't just a disease, it's a form of undeath and as such it overcomes any race. Massive's Vampire is just a disease, the human never dies during the change. Dwarves are very hardy against disease and poison in more lore systems, as are Elves. I imagine Orcs are very hardy as well. So none of them should really be susceptable to it. Plus a disease as complex as Massive's Vampirism would have to be very specific in the changes it makes, biologically. Even if an Elf contracted the disease, it'd probably function very differently because the genetic coding would be so different. On one hand this should rule out the possibility of having Elven Vampires. On the other, should the Vampire plugin ever be rewritten it could involve multiple races of Vampire. Similar to World of Darkness.
So basically, unless the plugin were redone, and an RP reason given for it expanding to other races (Maybe Baver has been experimenting on the idea for a long time and finally found a breakthrough?) it makes no logical sense for other races to be included.