Photos above are some great examples of what some HeroBrick.com customers have built using their own imagination from pieces they have bought or collected over the years.

Top row from left to right: USS Yorktown from WWII, Yamato Battleship, a custom hotrod with Emmet and Wildstyle
Bottom row from left to right: Custom hotrod and a Mandalorian Assault Tank complete with rotating gun fixtures and opening hatches.

The following photos are more great MOCs built from LEGO pieces by Marcello De Cicco, who is a fanatic AFOL (Adult Fan of LEGO). These photos can be used for publication as well:

USS Yorktown CV10 aircraft carrier
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=527993

IJN Yamato battleship
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=371053

Grumman TBM-3 Avenger torpedo bombers
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=462788

Youtube video from BBTB August, 2013
https://www.youtube.com/watch?v=Q9um36vTH8I

Also check out the great photos of MOCs at Bricks By the Bay taken by Norman Chan from tested.com (credit for the ones on tested.com should be given to Norman Chan/tested.com)