Gary
As you may have guessed, I'm very interested in using bamboo.  And not just for battens.  Here I have a free supply of the stuff, as much as I want!  So from a cost point of view it is very attractive.
The chinese used it in their junks for centuries so it can't be too bad.   Apart from the use in battens I also like the idea of using it for interior finish.  I'll be interested to see your treatment of it (if any) and the results there of. 
Interestingly, as I mentioned on a previous post, David and Lynda Chidell used it for battens, untreated, and only broke one batten in 4 years of sailing.....  Of course the loads have increased with cambered panels.
Peter