I tried, I did. But now I've gone back to trying to get off the bean. I'm amazed at what caffiene is present in the lindt 70% dark chocolate that I've been using to prop up my habit, to try and supplant it. One square of the delicious dark stuff, and I've stopped yawning, my eyes have cleared, and I can actually tell the difference between my left and right hands. Dark chocolate is tops, lindt 70% is even tops-er. 85% cocoa is still a little till chalky for me.
I am reduced to sniffing coffee grounds at my desk utill the yawn attack passes.