Hi Jim_Hull,
So far as I've heard, selling factory warranty extensions is not a standard practice throughout the industry.
On Landmark 365, I believe there is a 2/5 warranty. 2 years on the coach and 5 on the structure, if you have it inspected annually.
On a Big Country, the warranty is 1 year on the coach. The appliances are warranted by their respective manufacturers and in some cases have a longer warranty.
You can get third party service contracts (which some people call extended warranties) for one or more years. Good Sam has one where you can pick the term and the deductible. There are many others. But be sure you read the policy fine print before paying. What's included and what's excluded can vary quite a bit.