I am considering changing my room into a freeroam ferret room. A large dog kennel would serve as sleeping quarters. I would cover my floor with a shower curtain or two, and put fleece over the top, to protect the carpet below. A baby gate at my door would keep him contained, and I'd put two litterboxes in corners. The money saved with not buying or making a cage can be used to buy toys and pay vet bills, so it can have luxery. 

It would be much easier to purchased a playpen.  Then you don't have to worry about cleaning up the mess around your bedroom.  Having shower curtains on the floor.
They also make a mat for the playpen.

http://www.ferret.com/Search.aspx?query=playpen

The large dog crate I had would not hold a ferret because the bars were too far apart.  Ferrets can climb, too, so the best baby gate would be one that couldn't be climbed.  good luck.

THE DOOKS OF HAZARD

My room is actually very small. I could barely fit a small playpen in there. It wouldn't be too hard to keep them contained in the room. 
Do you guys think it would be okay for the ferrets? 

Also: I've begun making a "mural" that is just a giant collage of random ferret photos. I plan for it to be floor to ceiling (probably part of it will be removed for the ferts so they cannot reach), and even the ceiling will be covered. I hope to cover every part of my bedroom wall with ferret pics. So far, i have well over a hundred photos of varying sizes, from a stamp to a full sheet of paper. I am hoping to hide it from my boyfriend until it is done, he only has seen the pictures, but not on the wall.

A couple sections of playpen, like the marshall's 3 panel expansion, can make an effective door barrier if it's attached properly.
http://www.ferret.com/item/marshall-small-animal-playpen-expansion-panels-3pk/650345/

A couple hooks on each side of the door jamb is all it takes.

THE DOOKS OF HAZARD

Ooh, I'll look into this

My ferrets are not caged. They have a bedroom to them selves. So I would think it would be fine, as long as it's ferret proofed . Mine  love not having to be in a cage. I have all kinds of toys and sleeping places all over the room. I have litter boxes but I also use pee pads in the corners of the room b/c they dont always use the box and often miss. They are pretty good about atleast using pee pads so my carpet is pretty clean..

Current fuzzies: Ferngulley , Clementine, Clyde , Casper, Rose

Plus: 6 rats, 4 cats, 3 dogs, 2 turtles

hey, just came across this and wanna share my slightly different opinion:

i have kept ferrets in europe before moving to asia and here now too, and i've always build my own cages - wood based - without any issues (in terms of odor / cleanliness)

we have a ferret specialist in austria who recommended to do that rather than use metal grid based cages, as these are always open and exposed on all sides, and that is actually not good for the ferrets - neither is metal grid flooring which is used a lot here in asia too.

we basically built a 3 floor cage which is simply a closet type box construction with solid wooden back and side walls and then with doors (with chickengrid on) as the front. floors are connected through holes and with small ramps to walk up and down and each floor panel has pvc flooring glued on (also for a few centimeters up on the walls) which makes it super easy to clean. back in europe the whole thing was larger and partly outdoors so we didnt use pvc, we laid in tiles. all this is not expensive - just takes the time and effort to do it.

we're planning to stack up an additional floor these coming days, so if you're interested i can take some pics and share...

if you have the resources - always build them something nice rather than putting them in these metal grid boxes!