Sauzo, they put them on their side, fill them partially with dirt and use them. Works until a permanent enclosure can be built for an juvenile. Nobody in their right mind would use a grow tent for say a full size croc monitor or black throat and anyone that can afford to keep those can afford a full size permanent enclosure. These however are used as temp housing and quarantine rooms for young ones.
I am also not talking keeping a snake in there to live, this would be an enrichment play room so it doesn't escape. I guess I didn't make that clear.
Seriously if you can't build or buy a proper enclosure for a large reptile, you aren't ready for one. Main reason I don't keep them. I don't have the time and patience. Not sure what you thought I was assuming but I'm not stupid enough to suggest this as an enclosure.
As for a link, google grow tents. Growace is one site. Check your state for laws on hydroponic equipment. Some states are a little archaic.