I did a series of conversions to create Hecatrix Blood Brides for my old Dark Eldar army which were a lot of fun, and worked out pretty easily. This involved chopping off the hands of a few metal Dark Elf figures, and putting a splinter pistol in their place!
It certainly created the effect that I wanted... they were certainly different from the regular Wyches, but conveyed the feeling they were a good deal nastier.
She's also here:
One more look from ground level!