I know a lot of you have probably seen this article in the Bat House Researcher Archives, but for those that haven't here is the link. http://batcon.org/bhresearcher/bv5n2-4.html
Buy using the 6 foot 4X4 post as the base, you are already three feet out of the ground before attaching a longer 4X4 or metal pole as the actual house mount. A typical 16 foot post gives 13 feet to the top of the pole when installed three feet into the ground, whereas using the tilt post method you should easily be able to get 19 feet to the top of the pole. It looks easy enough for two people to install in a short time. I will be testing this method for my front yard rocket house. The little browns in my neighborhood are typically seen flying 20 to 40 feet in the air most likely due to the large amount of 1.5 story houses and tall maple/oak trees. Hopefully this higher mount will be able to attract them easier.