Hello,
We've got a client who has some very complicated programming needs. We are prepared to design the system from the ground up, but I am wondering what might be out there already that could take care of some of the features.

The website is a Real Estate website that entices users to sign-up for free workshops in several areas. The client wants several local portal pages for these local areas, need to be able to create new ones, and also needs to be able to add workshop dates, etc, and have it integrate with Infusion Soft for mailing lists. There needs to be several levels of access, editable regions on pages, different access levels that can upload files to different "groups", and several administrative features.

A user will sign-up for a workshop and eventually go from "Registrant" to "Attendee" to "Student", etc (based on manual changes made by an admin). When the user gets to "Student" level, they will get access to the forum and files area on the site. Also, InfusionSoft will receive these status updates and generate different mailings depending on the user's status as a registrant or student or whatever.

I'm wondering if there is an existing CMS system that may at least have SOME of these features. It would need to be one that is not commonly hacked and one that is easily customized. I know there are a couple that link up to InfusionSoft, but the other features do not seem to match what we need.

As I know, there is no CMS system like that, you should visit opensourcecms.com, many CMS systems there, choose one that fit your needs. But I think you have to do much on the script. Why don't you rent a coder for such big project?

Take a look at www.expressionengine.com - you can use it to create your local portal pages and restrict access to whichever user groups you define. The content in each area can be displayed however you want it so if you needed worksop dates in date order, or to be hidden until such a time/date it can all be done. Maiiling lists are controlled within EE as well and you can filter mailings to different user groups as you need them.

I'm sure if you ask on their user forums regular EE users will agree with me, and if you need some tips on how to set up EE to do this there is a lot of good help there as well.

Hum ... wouldn't drupal (http://www.webhostingtalk.com/www.drupal.org)be able to do some of this ?

I believe all the e-commerce real estate websites are all customized as I don't think there are any cms based on real estates. Would you be able to make a version derived from oscommerce? :p

I also think that Drupal is the best CMS out there. You have a very solid base on witch you can build almost everything you want.