Advanced CMS – using custom data and other databases

I’m using WP as a CMS for a site that I’m porting from an old, non-WP site. I built a pretty basic custom php/mysql backend on the old site for data storage, and used PHPRunner to build an interface to manage the data. It is basically a group site where there are several dozen “contributers”, who keep up their own profiles and data related to them.

In my conversion to WP, i have made extensive use of Page Templates and custom PHP in the templates to access a seperate database where all the data is stored. For example, see this page, which pulls Teams and Names from the database, then click any name and see a profile page, where all the data is pulled from my custom database
http://teamkendatire.com/wp/team/
http://teamkendatire.com/wp/teammember/?id=12
The team members now use the PHPRunner interface to edit their profiles and add Race Results and stuff like that.

I would like to move most or all of the data storage and management into WordPress, if possible. That is, I want members to be able to use WordPress accounts to manage their profile information, then WordPress data storage and retrieval to for stuff like Race Results and Team Schedule.

Is this asking too much of WordPress? Obviously it can’t be done out-of-the-box. I know there are Custom Fields on Pages and Posts, but that is not nearly what I am after. Are there special ways or Plugins to help me get where I’m going? I think it would require a plugin that can access special or non WP database tables and present them for editing inside the WP Administration interface in highly customizable ways.