I'd have gone for a 2 pole 3-phase induction motor with a decent quality VFD. That will run at close to 3000rpm at base speed. Go for an oversized machine like 2-3kW or so, so you don't need to change pulleys etc.

I don't agree with this current trend for using servos on spindles. Servos are designed for position control and VFDs for speed control. You can use a VFD for closed loop position control but servos are not so suited to speed control. As for the size of the motors, you can get induction motors in the same package as servo motors. While they are slightly larger, it's not a massive difference but a larger "conventional" TEFC industrial motor is considerably cheaper.