I don't have a sketch immediately handy, but maybe I can offer some information (and do a sketch in paint later if it sounds like something useable for you).
The first question I have to ask is how big are the rabbits that will be going in the cages? Will they be by themselves, or possibly have litters down the road? Will they be taken out regularly to exercise, or just live in the hutch most of the time?
The easiest method is to build a frame that holds premade wire cages, with a support cross beam running under the front and back of those cages, with a plywood back, sides and angled roof. That way, you can pull the cages out for easy cleaning.
I recommend figuring out what height is comfortable for you to manage the rabbits at (usually about hip height) without getting too expensive on lumber for legs. 2x8s make good hutch legs.
If you want to build the cages into the hutch (make the whole thing one unit), the cages themselves only have to be 16-24" tall (again it depends on how accessible you want the cages to be, and how much room you want to give the rabbits to stand on their back legs to look around).
I recommend making the cages only 24-30" deep, and then however wide you like (24" wide would be adequate for a mini rex, but you'd probably want 36" for a standard rex, especially if you plan to breed her, and then 48" might be better). For door placement, some people say to put them right next to the divider so that the divider acts as one of the framing bars (I use 2x2 as the divider frame, with wire attached to both sides of it, creating a double wire divider with about 2" of airspace between cages). If the individual cages are too wide for that kind of set up to give you access to the whole cage, put the door to the middle of the cage, leaving enough space for the feeder and water bottle(s) on one side.
Cover the floors of the cages with 16 gauge 1"x1/2" galvanized wire mesh, and use 14 gauge 1"x2" mesh for the front and dividers. Also keep in mind that any exposed wood, especially corners, will get chewed on, so you might consider covering it with hardware cloth or extra mesh (the floor mesh is more likely to do what you want it to, if you're bending it over corners).
Also, if the whole unit is longer than about 6 feet, you'll probably want to add a 3rd pair of legs in the middle.
If you're not going to just let their poops fall to the ground under the hutch, you'll need to set up supports for trays or a waste directing system (an angled board with buckets that have small holes drilled in them to drain away liquid waste under it works great).
I'm happy to provide better details or drawings of any ideas that sound like they might be useful.
