After killing at least a 100 of these things I have seen a trend in the ROG items. Most SI creature will drop ROG items for one or two lines.
Arbordons seem to drop a lot of shields and swords. I have gotten about 8-9 shields and 7-9 swords. Shields have been mostly medium with 1-2 small. Swords have all been one handed, left hand useable. Shields and swords are all yellow to 28-29 toon.