What is the reason for crossing labs with goldens?.
How much does the dog's structure besides height make a difference? If someone is putting weight straight down on a dog, would a stockier dog - a wider frame - be better even if he's a little shorter? Or would that aspect not matter?.
I wouldn't suggest Berners. I've never seen one that I would want to use as a SD. They can be great 95% of the time, but they have a tendency to spook and completely flip out on occasion, in some very unpredictable and odd ways.
I've never seen a bad Golden or Lab service dog . I met such a neat Golden today .
I know this may sound out there and perhaps to some, crazy but how about an APBT? or an Amstaff or American Bulldog? I know people with APBT's who are service dogs and I know people who have other Pit Bull breeds as service dogs and have seen some pretty great things done with them.
We also officially don't use rotties for the same reason, though one trainer I worked with LOVED rotties and got several that didn't look exactly like rotties if you didn't really know about dogs. They actually all (three) got released for resource guarding.
Gordon setter is a great suggestion, we have one gordon working now but I have never met her.