Thanks for the input, that's what I had gathered from similar discussions over at other forums. The price for a new 30 taper spindle with ABEC 7 bearings from Kent isn't cheap, but it isn't absurd either considering they are already precisely installed. If you take into account the cost of the bearings in the first place plus the spindle, the bearing install isn't much extra cost. I would keep the original R8 spindle and bearing assembly and simply cosmoline it and store it in bubble wrap and cellophane in case I ever sold the mill in the future, if I do go that route.
After reading about the pedal type and ball type grippers on various forums for BT30 tooling that people have managed to get working with various spindles for different machines, it would seem I would have to take a bare NT30 spindle and machine a recess for an insert with a chamfer, and get the insert hardened. Same thing if I wanted to make a ball type gripper, which seems like it would be more compact and a better idea. Assuming there is enough room inside a bare NT30 spindle to put in place such a system. A gentleman got a ball type setup working in a RF45 clone with an old Industrial Hobbies 30 taper spindle, which I assume is similar in outside dimensions and wall thickness to a Bridgeport style spindle just from looking at pictures.
Or I could just get a metric draw bar for a readily available power draw bar system and use the holders without a gripper end. The only real downside to not having the tooling setup with the grippers is I wouldn't be able to swap tooling over to the future CNC mill without first installing a gripper stud and vice versa. Which isn't a big deal at all, just would be annoying...