We live in a world of customization -- wherein you can have everything from the look to the actual function of a product changed to fit your needs. The only limitations tend to be time and money. It's like every customer has a personal research and development team waiting on standby for the order to come down the pipeline.
The world of adult fans of LEGO is no different -- in fact, it might even be slightly more advanced. You can get customized minifigs, weapons and stickers, but one of the quickest growing areas seems to be in customized sets. In addition to LEGO Factory, which offers you the opportunity to build a set using 3-D modeling software and then order the parts online, a number of LEGO builders have created custom kits with instructions and parts.
Brickmania (via Brothers Brick): A series of spy and war sets -- incredibly detailed tanks and fighter planes from WWI and WWII.
Mechanized Brick: In the same military vein, these kits would appeal to a history buff and LEGO fan.
Brick Brigade: LEGO Half-tracks and Tiger tanks, sensing a theme here yet?
Lionsgatemodels: This site sells a series of plans on compact disc, a number of town models to create a detailed layout.
Photo by Nich Archri.