Recently I got a new dendro that wasn't attached to any rock. I stuck a toothpick through it and glued it to a new rock. Right now it is trying to grow new root like processes to attach to the rock. I'll keep you updated hopefully with pics soon.
The rest of my dendros are still rocking along. I am seeing the most new growth from one in particular, that is located closest to the food outlet. I've had this one for 9 months, it is named "D2" if you go back to my post on page 1. It came with little baby dendros that have increased significantly in size and polyp number (relative to what they started with). The "secret" may simply be food concentration in the water.
Also here is a more recent pic of "D4"
The dendros are quite predictable in their pattern of inflating deflating. In fact they have been trained to inflate during the times that the automatic doser is running, just like with my sun corals. Seeing a predictable pattern may be an indicator of whether your dendro has acclimated well to your system or not. No matter what they always seem to inflate the most at night when all the lights are off.