Online games?

I'm sure if this qualifies as software design... but...

Perhaps some of you are familiar with such online games as Kart Rider in Korea, Maple Global (mapleglobal.com) or Ragnarok Online.

Assuming I had a large team working for me - quest development, world environment & character development, and writers and graphic artists for everything, for those less graphically intense games, roughly how long do they take to develop? Less than 1 year?

I want to put together a very simple online game for young kids. The game would have a system of instanced areas to hunt in, a large city world with more areas becoming available as a character levels up. Single and multiplayer games (yahoo type games) will be available. Character skill leveling and a large quest system will be included, as well as player housing with message board capabilities.

The game will be largely single player when in the hunting areas. Questing areas will be shared amoung players, though. The community aspect of the game mostly plays out when players are in their houses. The houses will be like homepages for the characters. They'd have their own avatars, guest books and diaries. They will be able to decorate their avatars and houses in many different styles.

Please keep in mind that I'm not talking about developing a huge online world - say like World of Warcraft or Everquest. I'm talking about something much smaller geared towards 7-13 year olds.

Any thoughts? I'm trying to get a feel for the team I need to put together as well as projected cost and time.

Thanks all