The 'bad' motor coils from the one in the photo are (about) 9 thick x 16 wide, or 144 turns per coil, about 5mm thick.
The multi-pole magnet is about 4mm thick, and MUCH stronger and with greater area than the other style.
They are mounted to a solid 1mm plate, along with all rest of the circuits.

My next plan,
if the coils can be removed, is a dual rotor with 2 of the same magnets, or maybe HD magnets, mounted on speaker plates (thanks Jerry!).  The speaker plates will be drilled and threaded for all-thread shaft, and a set screw will be added.
The air gap and magnet disks will be adjusted by turning the disks so the magnets line up, then tighten the set screw.
There is no need for jack screws from disk to disk!

That should allow for maximum area in the center, and use of common bearings.
Center area and finding suitable bearings are always a major problem for me.

All-thread is long bolt, 150mm up to 3 meters, with no head, a common product in the US.

A picture is worth a thousand words. Like this, but the speaker plate (magnet disk) hole is simply drilled and threaded.
http://www.fieldlines.com/story/2004/10/4/22201/3047