Hi Nepomuk,
Finding a projector that can do P3 for under 10K is unlikely. The better option is to go for a good Rec709 projector with good blacks/whites and contrast, and then use LightSpace CMS to make a LUT to convert fro Rec709 to P3 or DCI XYZ. This is a far better workflow. I always use TI Dark Chip projectors, not DILA versions - they are unstable and have very poor blacks.
For film grading, just use a film print emulation LUT - again via LightSpace CMS and a film profile of your lab.
As for Hubble and the new i1 Display Pro, the Hubble is a lot faster, and has better black reading capability. But, for the price the i1 Display Pro is very good value. I often suggest getting the i1 Display Pro and seeing if it is good enough for your application. If not, then get a Hubble as the cost of the i1 is low.
But, I have both, and always use the Hubble.
Steve Shaw
Mob Boss at Light Illusion