Like I said, I definitely recommend Exocontralto on youtube. He's an awesome guy, and you'll learn a lot from him and catch your jaw dropping every now and then. For the next box I'm building I'm going to have Home Depot cut it and then leech off of a friend and use his workshop similar to what you had in mind. Having Lowes cut your wood, is i'm sure a smart way to go. Pretty sure it's free as well, so that's a plus!
I might also suggest instead of paying hundreds of dollars for someone to build the box for you, to just skip half of the original work and get a skilled box designer like CarAudioFabrication (
Car Audio Fabrication - Custom Techniques , Video Tutorials Car Audio), or RAM Designs (
RAM Designs - Custom Quote) and have them professionally design the box for you. Then it's as simple as gluing and screwing it together for the most part. Good luck!