Changing Die Types

Has anyone on the list experimented with using a different die type than
a D6? I've been thinking about changing to a D10 or D20, so that I can
use more dice modifiers. As the system stands, you can only mess with
the dice rolls only so much (mods for shields, armor, etc.) so grafting
"Lock-on" ECM rules is a little difficult. If so could you post any
ideas to the list? The only thought I've had is that if you used a D20
you could have a much bigger modifier and still be able to hit.