Multi-user blog or CMS recommendation

[Kurt Granroth]

I currently use Pivot for my personal weblog and it mostly suits my  
purposes.  But I want to push this to the next level and Pivot won't  
bring me there.  I realize that I'm looking more towards a CMS  
setup... but I'm having a very difficult time finding one that fits  
my criteria.  Either none of them do it all or I'm missing something.

Here are my requirements:
1. Multiple users in one installation.  This means the following:
	a. Login mechanism
	b. An arbitrary number of weblogs per user
	c. An arbitrary number of categories per user
	d. Individual "themes" per user or per weblog or category
2.  Arbitrary number of categories
	a. Each category may have it's own RSS/Atom feed
3. Weblog-to-Mail plugin or mechanism (i.e., a new weblog entry is  
automatically emailed to a subscriber or set of subscribers)
4. Must run under Apache with php or perl and mysql (or no db) under  
a normal user account.  In other words, a typical hosted web account
5. Gallery2 integration (optional)

I have been cruising opensourcecms.org for a bit now and trying out a  
bunch.  Based on my experience there, I downloaded Geeklog, Drupal,  
and Joomla and have been experimenting with them on my home system.   
Unfortunately, due to a lack of documentation and a likely lack of  
imagination on my part, I haven't found a way to get any of those  
three to fulfill all of my criteria.

So, I'm trolling for recommendations, here.  Maybe one of those three  
can do everything and I'm just missing how?  If so, how?  If they  
can't, is there one that I'm missing that can?

Thanks,
Kurt