@Grelax - Its close without mods, but depending on how you set the tension on the cable either the top or bottom end is off. Its marginally acceptable without any changes, but the whole drivetrain will wear faster and the mesh will be off at either end of the cassette. Thats what I have seen anyway. I haven't tried any 8spd shifters yet. I can imagine the outside width of an eight speed chain might be an issue with the 10spd derailleur?

 Sram x9 nine speed. Currently only 10speed clutch derailleurs available. Otherwise I don't see the point. Further reading here... forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/dyna-sys-10-speed-compatability-9-speed-shimano-systems-646014.html

 I made a ally block to fit like yours, 6mm thick and with a small groove for the cable.
The gears shift great all the way down, great up from the middle to large cogs but not quite there on the lower cogs.
Would a slightly larger block cure the issue?

I did try it without the block and it wasn't good at all

I've just run the setup with the ally block at the Mega Avalanche and it was amazing! so good to ride a quite bike and not to have the sound of a brass band following you down the hill

 how have you been getting on with this? any problems? i am considering doing this as i would like a clutch on my bike to try and quiet it down a bit but want to keep 9 speed! also are you running a 9 speed chain?

 @reebs - The washer is .25 thick (height) with a slot filed down to .236 thick. None of the measurements relate to the width. You do however want the slot to be in line with the stock slot of the derailleur.

 Just tried the mod and it works! Did a 15 mile ride and my bike shifted perfect! My setup: Sram X9 shifter pod and a Shimano XT Shadow plus rear derailleur. I used a 6mm spacer.

 Roughly six months on the XTR shadow plus in the other pic. Zero issues. Ran this Zee this weekend. Flawless.

 dude. AWESOME. how long have you been running this setup?? Any issues after initial cable stretch and break in?

 Is the washer 1/4" thick or .236" thick? Which measurement relates to the width and which to the height? Sick mod!

 So SRAM 9 speed cassette/chain/chainwheel and zee rear mech all jive?....or do u need shimano cassette & chain?

 great idea, and very clean looking. nice job.

 What shifter are you running to this? Would a 9speed x9 work?

 Shouldn't 10sp shimano work with 8/9sp sram shifters without mods?

 hell yeah!