Joomla is not the worst CMS, and if you are willing to spend small amounts of money at a time you could check out joomlancers.com and post a project and get bids for a specific module or component you need. As for every site looking the same, that's simply not true. Check out rockettheme.com for some great premium templates that you can easily edit to your own needs.

You can use the free component "Community Builder" to allow registered users to create their own profile pages, and tweek this program and you can get the site just the way you need. The problem you will have is programming in the automatic subdomain creation and this goes for any CMS or custom programming. You may find you yourself with a pretty fluid site that users can edit their own mini-site, but you may need to manually create subdomains especially if you use a shared host of some kind.