In my opinion, 10 hp is too much to expect in a light machine like the one you are building. 5 HP maximum, and even that is pushing the limits of your current design. My recommendation is 3hp especially since you are thinking of doing 3D work, wwhich 90% of the time is done with small cutters or ball mills and at high rpms.
I think you will be pleasantly surprised what you can do with 3hp.
I would concentrate on accuracy and speed of motions and spindle rpm.

Just my thoughts.