Calvin, I am working with a lot of buyers, and while down payments can be a challenge, the bigger problem is finding a house that can fit their budget and needs. While there are FHA programs out there which can allow you to buy with as little as 3.5% down, they're really best for good condition single family homes. In Miami, we seem to have a lot of - not so good condition single family homes, or condos/townhomes. For either of these, you'll probably need a conventional loan - 20% down. You can also look to specialty programs such as Homepath and Hud, which can get your foot in the door, but you'll be buying a fixer-upper.
Give me a call if you'd like to discuss this in more detail.