We've implemented a small wrapper of the full Blogger API on top of the LiveJournal API.
So now you can use Blogger clients to post to LiveJournal.
Please help test this (it's now working on the test server) with different Blogger clients. The only one I've tested so far is w.bloggar, and it all seems to work.
To use moods and music, just put at the top of your post:
lj-mood: happy
lj-music: tunes
The settings you'll need for a custom server are:
Host: test.livejournal.org
Page: /interface/blogger
(We've mailed the author to have him add LiveJournal support, so future users of that client won't need to enter custom settings.)
The one screwy thing is date handling. We're always using GMT at this point. The blogger API doesn't seem to send a date. I presume Blogger lets you set your account's timezone? Or, do posts not have times? Let me know how this works.
I looked into supporting MetaWeblog, but it doesn't look worth it, considering it's basically identical to Blogger with some random stuff added and removed. Everybody who supports MetaWeblog seems to also support Blogger. Also, the MetaWeblog API is inconsistent, sometimes having an 'appkey', and sometimes not. I'm not sure what they were thinking.
I might add Moveable Type protocol support, but I can't find any good Moveable Type clients to test with. (what's the best client that supports their full API?)