In the beta we could see that there were many slots when u hovered over the ghost in the character screen. We can also revive dead ghosts. However, we can't get a new ghost. Why not? Idk...but bungie should include new ghosts for acquisition by either purchase or discovery. Not just different colors of the same shell but new and different shells like a cube one, or a sphere one. I'm not 100% sure that there aren't any new ghosts or that bungie plans to do something with this but to my knowlage...no. But honestly...new ghosts? WHY NOT?