Factories that could make off-patent bricks?
I suggest calling Lego customer service (1-800-835-4386) to ask them about a bulk order. Professional "brick artists" like Nathan Sawaya buy their brick directly from Lego. The bulk prices are decent as well. For example, through the LUGbulk program, we got 2x4 bricks for about 9.6 cents each (these sell for $0.30/ea on the Pick-a-brick website).

Also, here is a long list of manufacturers who can do custom ABS injection molding: http://www.thomasnet.com/nsearch.html?which=prod&amp;cov=NA&amp;what=Custom+Injection+Molded+Plastics&amp;heading=95958385&amp;k=abs&amp;x=16&amp;y=9&amp;navsec=modify