Have you considered using a capacitive reactance instead of a resistor to drop
line voltage?  I think I remember an RCA temperature controller chip, CA30??
maybe, that worked this way.  You can use a capacitive divider or a capacitor
sourcing current across a resistor to get low voltage AC and then rectify and
filter it after the divider.

Also, Supertex makes some high voltage depletion-mode FETs that are good if you
only need small current.  The advantage is wide input range.  I built a PIC
power supply that drew constant current from 12 to 240 volts this way.

- Mark Sullivan -