Small Indoor Hutch?

Hello!
Me and my fiance moved into a small flat about 6 months ago. I'm thinking of getting a house bunny! But I want to build my own cage, that will fit into a smaller space. I'm thinking the bun would be only caged when no one is home to make sure that they couldn't get into things they aren't supposed to. So I want it to be big enough for the bun to be comfortable over night. I also would like something kinda portable, as we have a nice outdoor porch that I would like him to be able to spend time on in the summer. So anyone have any ideas? My fiance is a machinist and very handy so he can build pretty much anything.
Thanks to everyone who replies!!!

Going vertical is easy to do with rabbits and can save on floor space. With a small breed a 24x24 or possibly smaller foot print should be able to offer them enough room if you go up 1 or 2 levels.

The problem is keeping the levels clean if your rabbit is not a tidy one who is good about using a litter box.

I have a 3 story "rabbit condo" (Google it ) that is a modified ferret cage. The levels are 12 inches above each other and off set so the rabbits can easily jump up or down to the different levels and not fall too far if they miss. Some people install ramps instead

The wire spacing on the middle and ground level is enough so "bunny berries" don't get stuck and the top level is a covered in a couple pieces of ceramic tile held on by wire that is easy to clean and offers a solid floored resting spot

Their litter box is on the bottom level and their food bowl, hay rack and water bottle are on the second level, over the litter box, as rabbits tend to poop when they eat

-- Thu Feb 19, 2015 7:05 pm --

I just read you other post - NO WAY a Flemish or any rabbit over 6 pounds should be jumping up and down different levels of a rabbit cage, they are just too heavy and will very likely to injure themselves by breaking a front leg in landing or whacking their spine