Unfortunatley, this site online provides links to other sites with lesson plan ideas for creating designs.
It offers no information on programs to use in creating these, only procedures for how to create layout plans by hand with paper and pen.
However, from this site I found A Lifetime of Color http://www.alifetimeofcolor.com/ and on this site you can participate in games in which you decide which designs are bad and are able to alter those designs. The most simplistic game is one on a playground in which equipment is looked at for quality and can be fixed to make a safer envirnment.
In the more advanced games, students can create thier own buildings (still attempting to figure out saving techniques), help the government with alien attacks, and create masterful art peices.