I'm using coLinux primarily to access partitions from windows for which there are no native drivers, like ext4 and btrfs. Is there a way to mount CoLinux partitions in Windows directly? I'm using samba right now, but it's rather slow. Is there a faster way, like cofs backwards?
No. I think no other way exist.
EXT2FSD works for reading ext4 filesystems, though not all of ext4's capabilities are supported.