Computer Game (Virtual World)

We need an online, browser based virtual world game built with a possibility for it to go mobile in the future. The game will be a feature in an existing site. The world will be cartoon-like The player will be able to choose and personalise an avatar. They will be able to choose a role or job in the virtual world They will be able to get 'fans' following their avatar. They will be able to spend and earn virtual currency There will be tiers that they can aspire to (e.g. if they wanted to release a record, they can sell it for virtual currency) Buy clothes, cars, houses, etc. I understand that this is very brief, but a ball-park figure would be helpful for a 1st class job. ALSO, if any games manufacturers have any games we could possible amend or tailor to our specifications (ANY type of games for the 8-16 year-old age range) considered.