http://mlmmj.org/ claims to be heavily inspired by ezmlm. I haven't used either so I don't know how well it works as a replacement, but it might be worth a look.
What gave you that impression? With `zpool attach` you can attach a device to an existing VDEV (single device, mirror, RAIDZ) to increase redundancy. With `zpool add` you can add a new VDEV to your pool to extend its capacity.