Re: customer area - possible or not?
Hi,
This should be quite doable. Tiki has a finely grained permissioning system and the Trackers feature could be used to do the tracking you need - the feature essentially lets you create a database, create custom forms for entering data, create filtered queries, etc.
If you want more specifics, you might try the developer mailing list if you haven't already. You can sign up for it at http://dev.tikiwiki.org/Dev+Mailing+List and it has power users following it.
Hope that helps!