StarWars.Com's Cargo bay has images up of the 6th droid in the series, R4-M9. While the name is the same as the white and green droid from the POTJ line, the coloring is different. His panals are a baby blue/aquamarine color, instead of green. They have him scheduled for a August release. So we have 6 so far, with another 3 to rumored to be revealed.
MTFBWY and HH!!
Jar Jar Binks