As far as I know, only the Harmony 890 & 890 Pro models are compatible with z wave so if you have one of those you are fine. Some older models used to have zwave built into them but all but the 890 have had zwave removed from them. Now that Logitech has decided to drop or sell their remote control products, there won't ever be a new zwave harmony remote, and that includes the new Touch.
My favorite remote (non zwave but x-10 and insteon compatible) was the MX500 theatre master but it is IR only so you need an ir-powerline converter to make it work with x-10. You could do something similar with z-wave if you used an ir-rf converter, however, my current remote is one which I would recommend, the Model 45608 Theatre Remote from GE - (in the interest of full disclosure, I am a zwave retailer and sell these products online). I like the 45608 because it does everything I need it to for my a/v equipment including zwave lighting and scenes but when used with my ir-plc converter I can still control x-10 and insteon with it as well.
This remote is the first time I have actually been able to eliminate ALL other remotes, and believe me I have been using and programming remotes for almost 10 years now, have literally 30-40 in my office and have used them all. A close second fav is the X-10 Icon remotes but again they are not zwave, just x-10.
In a nutshell I think if you have the Harmony 890 you are good to go, if not try the GE 45608. As far as other remotes, the Nevo Q50, Monster AVL300 are two that are zwave compatible, Leviton makes one that can do zwave AND control a few learned ir commands, and Wayne Dalton made a zwave A/V remote similar to the GE 45608 but I think they are discontinued as is the 45608 (they are both still available for sale though). You could also try an IR to Zwave RF converter but I am not familiar with them.
Another possible solution is using PC and/or iphone/android software with a program like HomeSeer or Mi Casa Verde's Vera3 or VeraLite controllers. I have used both and with an IR emitter/receiver you can do almost anything in any protocol.