If you flowered the seedling at about 4" and it doubled in height it would be about 8" when done. Add 4" for the tiny pot it will need and your up to 12" then the light on top will take up probably 2" So that's your 14" case and remember youll be doing this all for about one joints worth of weed. To get the seedling to 4" would only take two weeks (aprox) and then another 6 weeks or so of flowering. So youre looking at waiting for 8 weeks for a joint!?

Doesn't seem worth it to me. Take the some advice and scrap the computer case and think of something bigger in your house to make a discreet growbox out of.

Laterz