ECM questions from newbie

A few newbie questions.

(A) Does ECM support directly driving stepper phases(5 wire motors)
in a PWM fashion to accomplish "fine" microstepping?

(B) If it does, is it modelling a sine wave ramp between phase pairs?
(for constant power?)

(C) If I build a servor amplifier (digitial chopping) is there lots to
be had
by essentially making it a variable switching current supply feeding the
winding
compared to chopping voltage to the motor directly ?
(ie analogue filter prior to motor vs. "motor is the filter")

(D) I'm assuming that I can "mechanically" stack two 50Oz steppers to
achieve ~100Oz
holding power if I had to, any comments?
(I actually plan probably 3:1 or 4:1 belt reduction with the 50Oz Nema23
steppers
out of old apple imagewriter printers, carraige motors)

(E) has anyone pulled out the HP/Agilent optical mouse sensor chip/lens
to make a DRO?
Will EMC be able to use this for closed loop control even tho it will be
different than the stepper
resolution?
They have quadrature outputs you know...
I plan on using one for each axis for DRO...
the chips have outputs for 2D but that would be impractical to mount...
(400 counts per inch, there is a 800 cpi version too)


Wanting to try CNC, and being the tightwad that my lack of funds
dictate...
I've acquired a Homier little Orange dill/mill and Homier 7x12 lathe
from a show
earlier in the year, $399 for the pair :-) I'd like to use a single PC
running
EMC (dos or linux) driving the above weenie steppers... I could
probably start with
the PIC chip for converting dir/step into "fine" PWM driven
microstepping.. but I'm lazy too.

I assume I'll have to do some lapping on ways to get lowest possible
friction...
Do people lay any friction reducing tape down on the ways?

thanks
darrell