Unless there's been some major change with the development of 11 speed, I don't figure there should be an issue. Otherwise, how would KMC sell any chains?

 

I run an Shimano XT M8000 11-42 cassette on one of my Hard Tails
And I run a XG-1199 10-42 cassette on the other.
Both with SRAM PC XX1 chains you can't tell the difference.
I've also ran the PC XX1 chain with a 10 speed PG 1170 cassette and still no problems.

 

On another note, can I use an XT M8000 cassette only....and SRAM rear mech, shifter and chain? I am finding that the XT cassette is priced less than the GX and will also fit a standard 10 spd hub. Also looking at WT or ABlack oval chainrings to wrap it up. Any input on this mixed setup appreciated!

 

^^^Look above your last post ^^^
As for chain ring pick one I'm using the SRAM X Sync Direct mount on both my rides and I have no reason to change.

 

I've had two bikes with XT 8000 11-42 cassettes and SRAM PC1170 chains for the past 4 months — absolutely zero issues.

 

I would actually recommend the SRAM chain, see here

 

Why not just run a Shimano chain and use a KMC Magic Link? They will work on a Shimano chain.

 

Or a KMC chain? Of the chains I've run KMC are the ones I always come back to.