After seeing Zempt mentioned on a couple of weblogs where my peripatetic interest occasionally alights. I decided to download it and give it a try. I've tried two other Windows desktop blog clients, w.bloggar and another whose name eludes me, but was disappointed by both, either because of the interface or the lack of connection to MovableType. Zempt appears to be designed for MT exclusively.
I did have some luck with the blogging client in my newsreader of choice, NewzCrawler.