Today, I was checking the comments, and I was astonished at finding out about Samuel's comment in the post before this. So here I'm posting the state of stuff so far.
First, it's recommended you check the forum for uptodate info. But after seeing that comment, I'll try to update this too...
Also, there's this blog http://ssbclashweekly.blogspot.com/ it's not written by me, so it's better in that I won't spend programming time in writing the blog. It's kept by some of the mods/admins in the forum.
The music folder http://www.mediafire.com/?sharekey=3179d420e270875e5bf1f12f1ff3f30aa0238c601830cdde5621d66e282a0ee8 This must go in the root of your sd card inside a folder called clashmusic or whatever the folder in mediafire is called.
This test includes... lotsa stuff I can't remember... but most importantly, DS-DS multiplayer.
It's like one month old, the latest test have been released only to the mods and admins and probably the first public versions will be released to the "veterans" or people with certain amount of posts.
The latest additions have been mostly visual. After this visual remake, game modes are vital. Btw, all the stuff added for single player is immediately usable for multiplayer. They are not separate stuff like some approaches may end up.