Oh, bugger. Just reading through an old thread, noticed a link to my Yeti, then from that to this. Turns out I didn't round this one up.
I was running the bike with 8 speed, by using 9 speed shifters and mech but omitting the 11t cog, and adding a bigger 12t lock ring from probolt. I had to add a bottom bracket spacer to take up the slack, this went on before the cassette. I was using a sram 990 cassette, a red one I think. Then with careful setup of the end stops and the shifter, you would never notice the loss of one gear at the back. The reason I did this was because I like to use the big ring most often on the front, and by having a smaller cassette biased over to the right of the rear wheel the whole lot used to work better.
TBH, 10 speed chains seem to render this setup pointless, as the spread offered is better, so I cross the chain less often.
To round off this thread, after servicing the bike after the worst of the winter, the Cotic was sold last year to a second friend. He just happened to see it as I was adding new cables and oiling the chain and it looked fantastic, all polished and shiny. He loves it, but rarely rides it. :/