Try calling them a "retriever" instead of a "lab". Couldn't hurt. People used to get around the "No pit bulls" thing by calling them "terriers" instead.

Seriously, though, it IS hard to rent with dogs. And, in all honesty, after having our rental house TRASHED by dogs and cats alike, I can see why people are reluctant. We would have had to asked for a $2000+ pet deposit to pay for the damage those pets caused. And they were nice pets, seemed well-trained, etc. I think they were simply left alone in the house for far, far too long by themselves.

Could you get a certification on your dogs, like the canine good citizen certification? How about letters of recommendation from your vet, kennel, groomer, current or previous landlords. That sometimes helps a lot.