Oh boy. Yes, this is my previous line of work- and I loved it.

What I ended up doin was having a wysiwyggish interface like mini mce and tied it to a backend- and let users create stuff..

This is a last site that I made with a lot of what you're talking about Dolan Geiman- this is an artist's website- they need to put new news up like mad, and articles, and press, and this and that etc etc etc. Check out the press section. I haven't needed to do much work on this aftwards.

Make sure you GIVE power and RESPONSIBILITY to the client for content- otherwise you will be in hell, my friend. I advice against letting them upload actual html like i advise against chewing on razorblades as a sleeping aid.

I've got experience with that too.. on this site: gootees.com - but.. all of this other stuff : http://gootees.com/used.html is done via flat files.

If you like the dolan geiman site i'll send you the code. the interface is neat. all of it is on css. the site and backend are sepparattish.. you may be able to use some of it.