Every bank and situation is in fact different. I agree with many of the agents below on one fact, lending requirements have become stricter and this includes appraisals. I am vary familiar with appraisals as a former owner of a multi state appraisal company, and current licensed appraisal. In addition, I was an executive for a national bank.
Depending on the product, the loan to value ratio, credit score, borrowers assets, the lender or investor requirements, some lending products do not require a full appraisal and do in fact hand over $100,000 without a traditional appraisal - instead a computer models the value - call it Trulia values on steroids. Having said that, MOST people and properties do not qualify for this type of lending.
If your credit score is high, the loan to value ratio is extremely low, you have a strong balance sheet, wanting a variable or short term fixed rate loan, then shop around and you may find an institution willing to lend based on a desktop appraisal or automated value model (AVM). These loans are typically kept in the banks portfolio (hence variable rates are more typical) and not sold on the secondary market.
Hope this helps.