Pictured above is a hand-drawn concept art for a the proposed figure.
The Replicators special gimmick would've been that an alien came out
of the chest of the Replicator - the above artwork depicts this.
Pictured above is the schematics artwork for Duke. After the original
concept art was approved, detailed schematics would be drawn up to be
used to create the actual pieces.
Before action figures are molded in their normal size, sculptures and
prototypes are regularly made of the figure at twice their normal size.
These prototypes are called "Two-Ups". Pictured above is the
"Two-Up" of Duke.