Not trying to discourage you, but when I bought my now home, a 2001 Fleetwood, I was told by our buyer's agent that the average lifespan of a mobile home is only about 30 years. Mobile homes are built with cheap materials and there is constantly something wrong with them. Trust me I know...I own one. If you really want a house that you can be proud about, keep looking and find one that has been stick built or buy a modular. It will be worth more. Another bad thing about mobile homes is that regardless of whether they are on a permanent foundation or not, their value normally goes down. It depreciates the same as a car pretty much.
But if you really want an answer to your question, there are a lot of variables there. Are you seeking an FHA, VA or conventional loan? What does your credit look like? Is it selling for market price or are you getting a deal on it? What is your income to debt ratio? What is the condition of the house?
These are factors that will affect what percentage you get, how long you can get financed for, how much your payments are going to be, and whether or not you can afford it at all. Nobody on here would be able to tell you how long a bank would finance a house like this for. There are too many variables. Hope this helped.