Those coops sold on ebay and in some local feed stores all look cute, but they're generally very impractical. They're too small, the wood is flimsy, and the construction is very poor. A new book just came out highlighting 16 chicken coops complete with color photos, construction diagrams, parts lists, and step by step description of the construction. The best thing is that all the coops for the book were selected from this website. Here's the link:
Probably not. There are rules of thumb on this site, usually 4 square feet per chicken in the coop along with 10 square feet per chicken in the run, but that is just general. There are so many variables that go into it that there is actually no right or wrong number. In general, the more room you provide the better off you are, partly from the perspective of them not being as likely to become cannibalistic and start eating each other, plus you usually do a lot less work if you give them extra room. Think how often you get to shovel chicken poop, for example. The more room you give them, the more flexibility you have in how you manage them.
Part of it depends on your climate and management methods. If they have access to lots of space outside the coop from wake-up until sleepytime 365 days a year, and all they use that coop for is to maybe lay eggs and roost at night, you might be OK. But if you like to sleep in on weekends instead of getting up by daybreak to let them out, maybe you like to take a vacationb and you might have trouble getting someone to let them out first thing every mornoing, or you get enough snow and such that they have to spend any significant time in the coop, you could experience serious troubles.
I understand the need some people have in getting a coop that looks good in the neighborhood and I know how expensive it can get, but I think you are better off going bigger rather than smaller. Good luck!