I agree it will be expensive. But you won't know if it's worth it until it's done. Could very likely be a $500 mistake. So I'd encourage you to build the cabinet, mount the drivers, build your crossover, then hook it all up temporarily and test for sound quality before adding a bunch of additional features and finalizing the build. It will probably sound bad to start out with, and you'll probably want to tweak it in a few ways to get it where you want it. Once it sounds ok to you, then I would start adding features. If it sounds like crap and you're unable to fix the sound, at least you're only out a box. You can use the drivers and crossover to start a different project.
And I agree with tyella. Less typing, more building! We want to see pics of your progress by the end of the day!