Sounds like a hackintosh
Its the avenue I would have taken if my focus was not on low power consumption. Really its the only valid option for building an os x computer with a dedicated gfx slot at the moment since the mac pro lineup is old and priced in the clouds.
the idea of the hackintosh is cool but i've heard stories about how much of a pain it is to keep updated and making sure software plays nice with hardware. For me the main attraction of OSX, is ease of use. I don't want to bother with all that other stuff.
On the mac pro, I agree. Last year's update if you can even call it that was disappointing. I'm really curious as to why Apple has neglected the mp line so much. Hopefully, they do something awesome with it this year. Top of the line components and a new design (internal and external) because the current design is really outdated.