I was working on a C# + .NET client mid last year and stopped working on it as I had no time to dedicate to it. Its been sitting on my website with nothing happening to it since last september.
If anyone is interested in creating a client of this nature, full source is downloadable from my website @ http://www.markallanson.net/.
Code for about 50% of transactions with the LJ server in text mode are implemented. Full posting to personal and shared journals is implemented. Friend checking is implemented. GUI and Html journal entry editor is implemented (ms dcom control) w/ post security, moods, music etc.. (no music autodetection). Server history logs. journal histories are implemented.
Proxy support hasn't been done yet, but this is only really a 5 min job i haven't done because i havent needed it.
If anyone wants to pick up this ball and run with it, go for your life!