When I read your question I missed the "seller" part. I thought you were asking about getting financing in general on a mobile home. As Sandy mentioned it would depend on if the seller had a loan or owned the mobile home outright. We are seeing more seller financing in this market because sellers have to be more creative in getting their homes sold.
Erica Pittman-Gaynor of Keller Williams here. It is a bit more difficult than getting a loan for a condo or home but can most definitely be done. I just happen to have a mobile home listing and had a buyer making an offer. We recently went through the pre-qual process as well as the County First Time Home Buyer Assistance Program. It takes some time and you have to know who to talk to. Because of my recent activity I have a really good relationship with one of the few Mobile Home Lenders in town as well as the fellow at the County. If you'd like some help getting in to meet with these people don't hesitate to let me know.
Hope this helps, have a great day.