Moutain bike - clutch/brake lever??

I've been riding non-motorized bicycles for more than 10 years now. I have >50k miles by bike in that time. Whenever I'm riding, I keep my index fingers on my brake levers. I have my shifters set up so I can shift either direction with my thumbs. I have become very experienced with the use of my brakes and can now stop on a dime and give you about 8 cents change. I like the idea of having both brakes operated from the same lever, it frees up space on your bars and for me would provide much needed stopping ability.
I'm planning on building a bike for some speed and stopping a fast ride is a good thing I think