I lost the link, however, a few months ago, there was a website selling kits for a laser for around 150 bucks. If you look at some of the sites such as hackaday, you should be able to find a hack for those laser pointer pens to make them start fires/cut items. From what I remember, the hack is from removing the laser diode from old dvd burners. I believe that the main issue is the amount of infrared light that they emit. The following is a link for a diy laser cutter... It should be possible to use this to sinter iron powder. http://hackaday.com/2013/12/20/diy-laser-cutter/ I do not see a reason why we cant use this for SLS. We may have to use a different lens perhaps to improve the output.

In a few months, I plan on attempting this hack for the same reasons. If no one beats me to it, I plan on document my work. I cannot guarantee any of the patent availability.