+1 on the IMS shifter from Amazon. It fits my size 12.5 boot just fine.
It's steel, quite stiff, and does not rub on anything. However, like the stock shifter, if you try to mount it rotated ccw (lowering the toepeg) it will foul on the frame when you downshift. I ended up grinding away a little of the lever so that I could rotate it down one spline. It now fits my riding and shifting style much better.
I haven't noticed any weakness even with the slightly thinner lever. I am keeping my stock shifter for a while "just in case".