I don't have any plans to offer but the general outline is pretty simple, so I'll try to summarize.
First, everything is based on a single sheet of metal roofing from Lowes. That's the measurement from which everything else is based.
Materials list:
1 sheet of metal roofing
1x2s apx 8ft long from Lowes or lumberyard of choice.
1/4 or 1/2 hardware cloth (smaller is better because kits are suicidal)
Scrap plywood or a new sheet is handy
Some scrap 1x4s are hand for building the nest box
Take the apx 2ftx8ft section of metal roofing (the cheaper the better of course), and lay it flat. Take two 1x2s and lay them on top of the metal long ways. Cut the 1x2 s so that they are 4 inches shorter than the metal roof (overhang is crucial).
Then cut another 1x2 to build a frame from them. This shape should mirror the metal but be at least 1" shy of the edge in all directions. Now you have a rectangular frame. Build a two of these frames (one for top one for bottom).
On the bottom frame, run 1x2s the length of the frame with 1/4-1/2 inch between each one to allow for grazing (but acknowledging that if kits get out of the nursing box too soon, the slats are a death trap if they're too big). This will be the bottom. Miter each end when you trim them so that you can drag the bottom instead of it catching on the turf.
Now decide how high you want yours to be. I liked mine a little deeper, about 2 1/2 feet because does don't mess with trying to get the roof open if they can't reach it. Cut 4 1x2's in the same height and use them to connect your top and bottom. Now you have a rectangular box.
Using plywood (thinner is better!!)make a nesting box on one end. This provides structure and the nest box is mandatory, kits cannot live in the open air. Make sure to build in a hurdle at the entrance from the nest box to the open area so that kits that can't run and jump, can't get out, they will die if they get out too early so I usually used a removable hurdle that only the doe can get past and then remove it when the little buggers get big enough. One small hurdle should remain (apx 2inches) att the bottom though because I did mine 4 seasons and this helped limit the cold air in the nest box.
Once the nest box is built, take your roll of hardware cloth, screw it down with a washer and screws to the nest box, then wrap it around the length (sides) of the entire tractor back to the nest box on the other side. Washers are crucial! Get this tight, I used a makeshift brake to bend the corners because they were hard to get taunt otherwise.
Now its time to put the lid on. I liked hinges but always found that the screws let
water in. The crucial thing is the overhang as you don't want water dripping anywhere in the tractor. I was amazed at how dumb rabbits are. They'd just sit there with the water dripping on their heads, then die of cold if I had let them.
My best setup included a
bucket on top with 1/4 or 1/8 plastic tube to watering nipples for water and standard food box cut through the wire but the food always was a challenge with the elements so I'd suggest trying to think about how to mount the food box inside the enclosure with a way to fill from the outside without allowing rain to get at it. My system was not perfect.
Handles on both ends are crucial. I also like a drag line as my back sucks. I'll try to find some old photos but I hope this helps.