Perhaps your question may on-topic for Audio-Video Production, a 'Q&A for engineers, producers, editors, and enthusiasts spanning the fields of audio, video, and media creation'. They already have a few question on lighting.
DIY questions can be asked on Home Improvement, although the sites based more so on traditional practical lighting as apposed to lighting for entertainment.
You can also propose a new site on Area 51 (if you have the determination to do so). Making a new site is a fairly time consuming process which involves gathering plenty of like-minded individuals to commit.