I just picked up an "Incremental Clutch" from DW and I'm quite impressed by it. Basically it's a clutch that you would use on an x-hat that would allow you to adjust the tension of the cymbals simple by rotating the clutch itself. It works really well and it looks solid.
Video (fast forward to 7:10)
I'm using it on a Billy Ward inspired stack. A 21" Bosphorus New Orleans Ride over a 14" Bosphorus Hi-hat top and it works great. I can go from all manner of closed, open and in between during the song if I want by sort of pushing or pulling the mechanism with my stick.
I highly recommend it.