grange square did the ones in 360- place were Ed wallace works.. did a good job,

there grade 5 titanium 4mm square shafts that step up to 8mm round to have a pulley pushed onto them- then they go through an 8mm bearing, then step up to a shoulder, then back down to 12 with a keyway slot going into the wyachi wheels, and an m5 thread in the end to keep the wheel onto the keyway.. if hes still got the programe for it he might make another set up for you.

either way- id definatly make them so you can support the wheel by a bearing on one side or another