Just a note: I have multiple domain names pointing to different categories by their name, with the domains linking to the category, redirected at registrar. Technorati interprets the categories with domains as inbound blogs to the main http://nommune.com site – I can tell easily because of the difference between 0 and 1.
I anticipate multiple blogs in the short term as installing multiple blogs. Although I use the ‘admin’ to edit the one at present, posting to multiple blogs might be easier through w.bloggar or some such posting manager. I have read that multiple blogs is a direction for WordPress. Nucleus advertises multiple blogs, but I didn’t find the interface as clear prior to trying WP and didn’t get very far even with one blog due to not finding the design customization procedures very evident. WP testimonials attest to the availablity of this feature in the WP (admin).
One thing I have thought of regarding multiples is accessing a common template, or css, in a higher directory. Wikki Tikki Tavi – http://tavi.sourceforge.net – has some approaches to central installation for hosting multiple copies which might be of interest, besides being a very URI and FreeLink vs. FreeLink flexible wiki development.