While I'm still learning the mortgage end of the banking biz, I think I can help. Unfortunately what you're looking for might be very difficult to achieve. While many lenders used to go to 110% of a home's value for a loan, that has gone the way of the dinosaur due to a tremendous amount of defaults happening lately. You'd be fortunate to find someone willing to go to 95% in the current market. That being said, your best bet would be an appraisal. The trick is to find someone who works with the bank or mortgage company that will appraise the property for what you're looking for or possibly more. Many places use the "tax assessed value" when doing a loan. Often times an appraisal can add quite a bit to the value. The down side for an appraisal is the cost. Often times they run $600 and up. The other thing is that many companies have a select list of appraisal companies they will work with, which can add another ripple to the problem.
Good luck, sorry I couldn't be more help.