Hydroponics - Kits, Systems, Videos, Books and Grow Lights
That looks like it would be perfect, kind of pricey though. It would be tough to have an airtight smoking tent that didn't suffocate you, you're gonna need some kind of airflow.
http://www.higherpeak.com/files/Home...titudeTent.pdf
That might be closer to what you're looking for, it says it's about 50$ in materials, but I'm sure you could trim it down a bit. But really, look at the picture in that file, it's NOT gonna be stealth unless you could build it in your closet or somewhere out of sight.
http://tinyurl.com/cpcckc
That might help you if those first two links don't