Yes, some private servers are very close to blizzard standard servers. Some of them are funservers, for dicking around, and making unstoppable characters, and some of them are higher rate servers with some modifications so that you can go even higher level and such. The server that I was playing on had a max level of 85, and had some custom items for 70+ characters. You still had to make money to buy them and such, but moneymaking was pretty easy since you could take all the vendor trash from lv 60+ mobs and usually make like, 100-200 gold per inventory, which doesn't take long when you're dropping like, 5-10 trash items per mob. But, making 2k gold for each item to get the high level raid tiers still takes a while.
There's a lot of selection on these servers. I personally enjoy playing on them occasionally because you get a slightly faster game, depending on which server you use, and you can meet people easier, since there's usually a decent amount of regulars who you get to know.
Also, I'm kinda used to playing private servers since I've been playing on them in some form or another for like, 5 years now (different games, of course, lol. I think it started with mu online, though.) [Which happens to have the WORST server architecture I've ever seen. 8 programs with the main server program taking 300+ MB of ram, totaling about 800 MB of ram? No thanks....]
