One other possibility, if the house is cheap enough, is getting a hard money loan for the purchase and rehab. Then you'd refinance with a conventional lender. A hard money loan is very expensive--around here it's about 5 points and 12% interest for a maximum of 6 months....it's the points that really hurt--but the loan is made on the after-repair value of the property. So, for example, suppose a property after repairs would be worth $500,000. A hard money lender will lend about 65% of the after-repair value, or $325,000. But if you can buy that house for $250,000, you'd have money for the points and for the repairs. You have the work done, apply for a conventional mortgage, get it reappraised at $500,000, and you're fine. (Some lenders might have a problem with seasoning, but that's a different issue.)
Hope that helps.