I was hoping someone else had a suggestion, since I've been on the same hunt.
I've had the same issue with most CMSs--they seem targeted at people doing either news or blogging, where I just want something to manage structured content with a couple of levels. Categories, with sub categories under them, and content-filled individual articles/whatever under those. Is that really so much to ask?
Here's some things I've been checking out; maybe you'll have luck with them, or maybe somebody else is using one and can offer a suggestion (links at the bottom).
*Typo3: This is one huge, beefy piece of CMS software. Multi-tiered content, massive flexibility in format and types of content, integrated database tools, multiple data types, image manipulation, multi-user/usergroup-based editing privleges, the works. I got it running just fine on my DH account, but I'm seeing three issues:
At least during editing, it seems to hit the MySQL server very hard, so conueries might be an issue.
I haven't yet gotten it to publish static pages properly, which it can do and would deal with the conuery issue.
It's very, very powerful, and as a result very complicated--it does way more than I'd ever want, so it's hard to get used to and probably overkill for a lot of people.
*BolinOS: Very cool-looking software, but at least as of the version I tried the stupid installer required a root MySQL password so it could set up a database, when just letting you create one would suffice. Perhaps in a future version this will be fixed.
*Midgard: Very powerful, but you usually have to compile this one to run it on a server (which might well be possible on DH if you know what you're doing). A project has apparently started to offer a PHP version so that it'll run standalone. Haven't tried it yet, though, and I can't find the link right now.
*Glossword: This is designed as dictionary software, and does a spectacular job of that, but it could also be useful for any sort of content that has a number of different entires and is alphabetically organized; you can create multiple heierarchical categories, with the unit of content being "dictionary" sections, each of which can have entries that are automatically sorted alphabetically. Very nicely written, runs great on DH, but obviously not for all uses.
*Firesite: Looks promising as a very simple CMS, runs on DH, but currently way too early in beta to be worth using.
*Webmake: This is one worth checking if you're a hacker type, or really like to see local files; it's not exactly a CMS, but a Perl module that'll take structured data from files and automatically build static HTML pages from it based on templates, regular expressions, Perl code, or whatever. You can run it locally on your own computer (which I'm doing), or I think there's a CGI version that you can run remotely. Downsides are it's lack of fancy network integration/management features, and it's hard to get started with (assumes a pretty good knowledge of basic Perl concepts). I'm liking it a lot for generating tidy HTML pages without having to hand-paste into templates, though.
That's about all I've got so far, past the usual Nuke-spawn and variety of simple Blog-style CMSs. What I really wish I could find is a nice program that'll allow flexibly formatted hierarchical content like Typo3, will build static HTML like Webmake, and let me use my own directory structure so I don't have massive ammounts of mis-linked traffic pouring in. So far, no joy unless I write one myself. Oh well.