What are you going to use for shifters? I don`t know you`ll be able to get any Shimano shifters to index with a higher sprocket count (more sprockets = more finickier), but I did use S.T. indexed shifters and derailler on a 7-speed Shimano HG freewheel for a while. Now I`ve got the same S.T. derailler with Shimano shifters and freewheel and it indexes like that, too. And you can always run whatever friction shifters with whatever derailler, of course. You can check the max sprocket size for your particular Cyclone at Disraeligears- it looks like the GT models (Suntour`s designation for long cage) mostly go to 32t max sprocket and 36t takeup.
http://www.disraeligears.co.uk/Site/...railleurs.html