I know what you mean. I"m sure it would work great for a cabinet. I"m actually in the process of building one myself, not from a freezer, but from wooden cabinets.
I would suggest that you prop it up and open it like a typical fridge. You'll be able to grow a little higher, because by the time you factor in how low the lighting will be(unless you're using floro's), there's probably going to be less than 30 inches. My first and most recent grow(as you can see I'm new to this), i think I stressed her into hermie because I tried to keep it low and bushy with perhaps too much pruning... At any rate, you may not have enough room, leaving it on its intended resting position.
Here's what I"m going to do, and you can take from it what you like:
Using a Euro reflector, which incorporates an inline duct fan, 160 cfm cooling a 400 watt hps system. The air is being pulled in from the back of the cabinet on one side, goes thru the light and out the back of the other side. And that air is not coming into contact with my plants. Then I'm using a carbon filter attached to another inline fan for air exchange/cleaning.
I'm going with fixed light system, in other words, I will not move the lights, but will have shelving to adjust during the different life cycles.
Some may opt for adjustable lights, but I've given it a lot of thought, and it's seems easier to cool the light if you make it stationary. I"m sure its possible to do it with both, but just seems easier for me.
...whatever its worth.
