Small Setup Help

I wanna try Hydro ... something I never even thought of doing before. But due to limited space I was only hopeing for a small 2 plant flowering chamber. I want to use the method the guy uses in the Mr. Green Video but I can't think of the best container size for the two plants ( I was thinking AT LEAST 8 inches wide by 8 inches deep by anywhere from 18 to 24 inches long) but giving those demensions i can't think of a plastic "source" to use as the planter tray. Please hook me up with a few suggestions!
Thanks

maybe an under the bed type of rubber made tub? ive got 1 thats about 30"x20"x6" (LxWxH). but they do sell smaller ones.

Wow thanks I would have never thought of that to tel lyou the truth haha