I've been trying to get this one done for a long time. Not easy to get good reference pics, especially for scale. Even asked here on the board a couple of times...
If it's any help, I believe the same greeblie is used on the "snowtrooper commander" costume as well as on (some of the) Cloud City Ugnaughts.
I sent what reference pics I had to a friend who promised he'd attempt doing a CAD drawing.
If and when he comes through - I'll post pics.
If someone already made one - I'd be very interested as well.
/Pontus