Plans are in the works for a sort of pen which will really be a larger version of the wire cage they live in already. I am in the drawing stage right now and will post a sketch as soon as I get a workable construction plan. My idea gets more complicated as I need this to be an indoor solution as the weather here seems to remain ridiculously hot. I am looking at something along the lines of 36"x60". Don't think I'll find a drop pan that size so I'm looking at alternatives.
The X-pen on the floor thing is just too messy for my fluffy little guys. Biggles and Charlee lived in our unused dining room (house rabbit style) for the first 5 months of their lives. Biggles' personality became like that of a small dog...super social. I later found out that is his personality regardless of X-pen or wire cage. He's just that rascally. It was great having them nearby, but a full-time job keeping them and their area clean. I could not imagine how someone with a real job keeps up.
Anyhow, all this lab rabbit research got me thinking of the idea of having everyone in pens. That is what initially got me thinking about a large wire pen with a wire floor that is more compatible with wool upkeep. More room to exercise was a big motivator. I am convinced that rabbits would benefit from a more social environment(as indicated in the lab research), but cautious as the current show rabbit model has a lot of supporters, and quite frankly, most of these folks are quite knowledgeable..even more so than many general practice veterinarians (as a result of lack of exposure). There is something to be said for experience. Besides, the labs are not dealing with show animals where nips (and subsequent white hairs and scars) and excessive grooming, such as nibbling on a show coat, can be detrimental. I have to admit that I am hesitant about deviating too much, but wish to do what is ultimately best for the rabbits and myself. It's all about taking the calculated risk towards innovation, emphasis on "calculated." I'm sure that someone else has done this. I would love to see their results.
I'm not quite going with the colony model just yet. My rabbit have been individually housed, but I am not above a little carefully constructed experimentation with future litters, if any. Our first two EAs (two bucks - Mr. Biggles and Charlee) were a bonded pair and they really seemed to enjoy each others company. They continue to be housed side by side. They are often found cuddled up to each other through the wire so I see how a group setting would be advantageous for overall health (not to anthromorphize).
Just a note: there seems to be a lot of research about group housing, but they mostly utilize solid floors and hay as bedding so disease (coccidiosis, etc) can be an issue. I think if they researched the benefits of wire/properly slotted floors in a group setting, they would experience a decrease in disease issues.
The idea of keeping my rabbits in larger pens just makes sense to me. I know of at least one other rabbit person who does this as a sort of outdoor exercise pen. The wire will help keep everyone clean. The rabbits get room to actually do more "rabbit things" like hop around and stretch out their legs. I am excited to have some sort of idea in my head as to what I would like...now to get it on paper.