The development of Descent 4 was attempted multiple times by various organizations.
Listed below are links to some concept art for each rendition of the fourth installment of the Descent Series.
Into Cerberon - A mod for Doom III which emulates Descent style gameplay.
Volition - Volition's concept art for Descent 4, later became Red Faction.
Midnight Squadron - A gaming clan turned development studio, Midnight Squadron started the community driven Descent 4 movement, worked on various mods for Descent 3 along with an independent game dubbed Project Vertigo.
Orbital Design Studios - Broke away from the Midnight Squadron, led by Charles "Valin Halcyon" McKee, attempted to create Descent IV: Invasion.
James "Kuman" Ku - Created various high quality 3d renderings of Descent elements.
Daniel "Darkbishop" Leontiev - Created various high quality 3d renderings of Descent elements.
Nick "Kruel" Herres - Created various high quality 3d renderings of Descent and concept elements.
Bubbalou - Created a detailed representation of the Pyro as well as various Descent icons.