Hi 2navret,
Welcome to the Heartland Owners Forum. There's a great bunch of friendly and helpful people here who are quick to reach out with help when needed. If anyone has added a motorcycle lift I'm sure you'll hear about their experience.
One thing to keep in mind is that Lippert manufactures and provides warranty on the frame. I'm sure if you called them, they would tell you that you would void the frame warranty by adding the lift. Also, your dealer is probably understating Heartland's opinion. I doubt they would say they "don't recommend it". More likely they would say "not supported" - which means if you have a problem, you're on your own.