James...hopefully, you've found a willing seller by now, but if not, there are some great Seller Carryback opportunities currently in the market. And, Seller financing is a great way to go! As others have suggested, you'll need to have a substantial down payment (minimum of 20% and likely more)...the interest rate might be just a little higher than normal market rate, but you also don't have to pay financing points and other upfront charges a lender would charge. Make sure that your agent knows the ins and outs of the proper paperwork and I HIGHLY RECOMMEND that you have the carryback servicing handled by a title company...they perform a great service for buyers and sellers by keeping track of payments made, interest paid and 1099 reporting, but they charge very little for the service. Usually, I suggest my clients split the upfront fees and monthly fees equally between buyer and seller. Expect that the Seller will want a credit report from you...they want to know they're doing business with a reputable party.
One caveat...make sure you fully understand that there will likely be a balloon payment...5 years, 7 years...something like that. Make sure you are absolutely confident that you can pay off the note or refinance at that time, or else you risk foreclosure.
Good luck! We recently were able to find a wonderful home in Scottsdale for clients with a 20-year amortization (no balloon) and a decent rate with about 25% down. Sellers are more willing to offer these terms in todays market...the security of this income producing event is often more attractive than the whims of the financial markets.