wondering if someone can help me with a website application question.

I need to build a site that allows users to register, filling out a number of fields, address etc, and then be able to login later and access their info, change it, add to it.

I’ve looked around for an “out of the box” solution and this includes CMS’s such as Mambo, Xool, etc, basically all of the fantastico suite.

I’ve installed them all and while some get close, none allow you to customise the fileds that a user needs to fill out.

Is this possible? I mean something off the shelf, or am i going to have to pay someone to build the back end for this site?

any help greatly appreciated.