Hi Alan,

from the days of repairing TV's I remember the permanent magnets on certain 
"coils" too. Guess they used this to distort the current waveform in a 
controlled fashion for the deflection unit.
About the DC-bias winding: Sounds a bit like a "transductor" - ancient magnetic 
component, sometimes called magnetic amplifier. The basic idea was to control a strong AC 
current with a weak DC current. But I cannot imagine these are used in SMPSU's.

About the slots in ferrite rods: Yes, they are used to reduce eddy currents. 
Especially in those high-permeability types which are more semiconductors than 
insulators (you can tell with an ohmmeter). I have a large bundle of them in my 
radio-direction finding antenna for VLF ;-)

Regards, and have a good LF season,

Wolf DL4YHF