Your strategy is a good one, as rates are incredibly low on the conforming loans (under $417k).
Yes, piggyback loans are still available, as long as you have good equity in your home. Most lenders will allow a second mortgage or equity line as long as your total loan-to-value ratio does not exceed 70%. Some will allow that ratio to go as high as 80%, one will allow up to 90%.
Our company is lucky enough to have relationships with some of the smaller community banks and credit unions -- that's how we are able to offer the higher loan-to-value loans that you might not be able to get on your own, or through the big box banks.
Guidelines change constantly, so if you are interested, please don't wait to look into this.