Fair comment Dave, and I acknowledge that your starter is the 'bees knees' but FWIW I just can't afford one at present, on the other hand I do have the ability and most of the bits to repair or upgrade my own as is.
The blind side bush bearing is 3/8" i.d. by 1/2" o.d. by 3/4" depth and is marketed by Oilite as bush AA-521 - price $1.50. The Torrington B 118 is $6.50. I have 2 end caps so might try inserting another roller bearing in the blind cap - perhaps INA SCE 610?
I have an old Harley Prestolite casing bought for $10 and some spare Accel field coils if needed bought for $10. The increased diameter worries me slightly though, as if I remember correctly magnetic flux declines as the square of the distance between the poles, so any increase in armature to pole distance may result in reduced torque?
Brush plates, brushes and springs came to $24 from an outboard motor place.
The Armature is OK, mainly as a result of not having been used for most of its life!
My primary was rebushed for the SM by Norman White some years ago in the UK, but I do take your point (might be interesting to insert a sealed ball here as well).
Mostly I'm just doing it this way for fun though...;-0
Kind regards
Luke