My LO through Academy Mortgage said I needed a 640 to qualify for the current going interest rates, but that she could get a me a loan (FHA) with higher interest and closing costs at 620. There are also lenders out there that do 600 and I know one gal here who got a 580+ (She paid over 5% I think). It depends if you are willing to pay higher interest, i think - the lenders are out there - you just gotta look hard and you can put up a post asking for referrals from those that closed with subpar scores.
Have you figured out why your scores are where they are and if there is anything you can do to bring them up? I went in on a short sale last summer with 590'ish middle and made it up to 653 in just 3 months by living over in the Rebuilding section and doing everything I was told, and then some.