I read that display duplicate content may bring down the PR of your primary domain. I had a PR6 ODP listing, but I took it down because I didn't want it breaking my domain. Looks good otherwise, I just warn you of that risk I read about.
Jeremy, I understand that you want to do this because then you'll increase the numbers of pages indexed in the search engines, so eventually the Kingbloom directory will be even larger than dmoz it self! Maby it's an idea to connect your directory to the dmoz clone, what I mean is for instance I'm on this page: Science (http://www.kingbloom.com/35-kingbloom.html) there's a link to this page: Science (http://dmoz.kingbloom.com/odp.php?browse=/Science/) So if I'm not able to find the resourse in kingbloom directory, I can search the dmoz listing easily with one click. Good to see almost 20000 listings are into kingbloom directory, I'm awaiting to see your directory script.
The point is to enhance the viewers experience. Like I said, I was bored. Yes, I have heard of others getting penalized for duplicate content. But there really is none here. The data is cached. Besides, I think you will find the content looks a bit different page per page than viewing it directly from the ODP site. I've not done a mod/re-write and am not sure whether I will.