As for a chain, just find a quality brand like EK, DID, Regina, RK, etc... I've been happy with DID, EK and RK brands lately for my Zilla. 

Remember if you are replacing your chain, you should replace both sprockets too.  If you don't, your new chain will 'wear' / 'stretch' to match the condition of the sprockets quickly.

I'm not sure if Shawn is still building these,

http://www.suzukiquadracerhq.com/index.php?action=store;sa=view;id=29

Run a HD case saver for a little more added protection against case breaks.