I've used the little green house units you are talking about and absolutely love them. Have actually considered how I might adapt one for a very small brooder ... but that's the subject for an other day. My units are only 2 shelves high. I'm not sure if the taller unit would be tippy in the wind, probably not if weighed down well with seedlings. On the down side, the plastic tent is prone to melting if left laying in the sun. When you take the plastic off to harden your seedlings, be SURE to put it under cover. I made a little rolling cart to place my 2 units on to make it easier to move them in/out of garage (I keep them in at night and during very cold weather) they definately extend the season. An other thing you can do is take the shelves out and push the bottom legs into the soil for a mini tunnel in the garden. Weigh it down to protect from wind taking it.