This can sort of be done now with the blog. The blog in CB allows you to enter HTML. I haven't done any hard core testing of which tags are allowable, but tables and links are a definate, and the tags can use the style attribute to apply formating. It does look like a bit of a security risk though, and I would definately recommend restricting user blogs in the robots.txt file.
I'd love to see a wysiwyg in place of the textarea, and when I get some time, I'm going to see if I can't replace it myself.