Changing 10.6.8 from mounting ext4 as read-only to read-write with OSXFUSE & fuse-ext - in fstab?
I finally found something that worked, and I have verified it does as well. Please see the link: http://www.dbsysnet.com/how-to-mount-ext2ext3-linux-volumes-in-mac-os-x-snow-leopard-with-readwrite-access/

Basically there is a mount option that can be added "rw+" to the file:

/System/Library/Filesystems/fuse-ext2.fs/fuse-ext2.util 

under the Macro() function.