I have a 2008 6 seat ruff and tuff. I'm in the process of adding 3" drop spindles on the front and extending the rear 3" by replacing the shocks and the leaf spring attachments at the rear of the spring. I'll call it 16 inches fully extended. Local auto shop claims the part number is HEL2-2920000 although I didn't have much luck on that one.
Here's the original shock: