I can't say much because I use wire cages currently but one thing did come to mind. Well... a few things.
You'd need quite a large area for them to manage on just what grows on the land. I've figured that to
feed a doe from the first day of pregnancy until the time when the kits are large
enough to butcher (8 weeks) it takes about fifty pounds of pellets plus some
hay. This accounts for all of her eating during pregnancy, lactation, nursing and weening plus the amount the kits eat from about 3 weeks old until the graduate to "Freezer Camp" at about eight weeks old. This is assuming an average litter of about 10 kits and an average weight of 5.5lbs at butcher time. Forage will vary through the season so keep this in mind. It's a lot of food to be growing in a short time. Some of it will be trampled, manured and just not eaten too.
I've also figured that I get about a wheel barrow ( a large one) full of manure during the same cycle described above. It will accumulate as it is very dry and dense. A worm bin is the easiest solution for breaking it down fast. Left on the ground it will build up unless you have a serious worm population in your soil. Even still it needs to be somewhat wet for a worm to deal with it and the
urine tends to deter the worms somewhat.
The urine is another thing all together. Rabbit urine is very concentrated. It will eat through
wood and corrode some metals if allowed to stay in contact with surfaces. It's tough stuff and rabbits tend to use one place to
pee, so it all ends up in one small area. Even though I move may cages seasonally, nothing grows under the urine areas. An adult rabbit drinks about a liter of
water per day and a doe with a litter will easily drink twice that. A litter of 10 kits 5-8 weeks old will drink about 4 liters on average or more per day as they grow. More in the summer and less in winter. They make good use of their water intake and that is why the urine is so concentrated. A lot of water goes in but little urine come out.
I like your idea though I might suggest having a few of these such areas. You may also consider permanent locations for breeding does that have a good burrow or nesting area. A separate area for the buck would help avoid some of the territorial issues that sometimes crop up with rabbits. Some does will castrate a buck for being too "forward" when she's not in the mood. A third area with forages for growing out your meat rabbits is a great idea.
I'm personally going to be trying to
tractor my rabbits through my garden paths. Basically I'll just add little wheels to the cage bottoms and let the growers mow the space between my crops. I want them just up off of the ground so they don't have soil contact and so that they don't end up with their feet in their manure. We'll see.
Let us know how you make out. Best wishes