You'll just have to spend some time poking through them to find one that suits your fancy.
I don't know of any bolt-on user management/authentication system that will, by default, create a blank "page" (whatever that may be) for new users the first time they log in, but adding that on would not be a difficult task at all once you had everything else in place.
After looking trough all ready made scripts, i decided to just create one myself. I started learning php and now i almost finished a script that does exactly what i want
The script can create new users, serve the users theire own page with information, advices and results of tests they've done on the website where you also see theire progression. I can keep them up to date with adding advices and comments to theire own page and they can send me responses. It's pretty fun!
But ontopic, if it's completely finished i'll release it for free.
Yes, be a part of Open Source Community and show the WORLD you hate to hide Knowledge.
One thing More, if you did not notice.
Make your User Management Class Based.
Hack Post Nuke User Module for Learning (E107 has also good one but more Advance)
Document Your Classes.
Many of Student may help you in this. Thats why Open Source Community Grow.
Better to make Component for any open source CMS to get Attraction and further Developement.