In addition to the impressive work gone into Palisades professionally released goodies, they led on to more in development (often with demonstrations) that was never released.

A good example would be the Phantom figure, an impressive 16" monstrocity that was advertised but not released on account of time contraints and the fact that they allegedly couldn't get it to stand on its own.  When auctioning off one in January of 2003, Palisades stated that there had been six prototypes made, but that they would only be selling the one.  The fate of the one and the other five are veiled in mystery.

Another fun abandonment would be the minibusts.  Several prototypes were auctioned off in 2003, of various stages of completion, including Hein (painted), Sid (left bare), and Aki (without the scope, one painted and one not).  According to a report, there was also a Ryan bust on display.

In the same report was a mention of resin statues, aside the resin busts, of Aki, Gray, and a Phantom.

Lastly are the prototypic action figures.  For the most part, they are very similar to the produced kind - with the exception of certain stuff (expressions, colors, and costume details) changed or lapsed.