Regarding the Broadhead Penetration study by Dr Ashby - I have a little input based on my own experience.
The testing he did was mostly on Asiatic Water Buffalo. These are incredibly tough skinned animals with very thick ribs andI found itwell worthwhile selecting a broadhead and arrow setup based on his recommendations.

For buffalo (and to a lesser extent on otherbig game) I set up the arrow as follows (in order of what I deemmostimportant)
1) Weight - 800g is good tho up or down a little doesnt hurt (momentum is key here - your bow imparts more energy into a heavy arrow than a light one)
2) Broadhead - heavy, single bevel, 2 blade, tanto tip, and a long narrow profile. Its hard to push something wide with 2 bladesthru a big bone - let alone 3 blades!
3) - Everything else. I like an extreme FOC arrow with a very slim shaft - it slows a touch less on the hide/ribs, thearrow shaft isa little thickerand you get a touch better pentration (plus they look cool!)

I also like to shoot 80lbs on buff - better too much than too little =)

And I agree with the other comments re thissort of setup not being necessary on deer etc. For animals with thin skin and a lighter framei use a mechanical or 3 blade head and alighter arrow. No need to use a sledge hammer to crack a peanut =) Plus you can cut a bigger hole and pull em up much faster.
Id be interested to hear what you guys who hunt bison and elk use for an arrow/broadhead setup - but mebbe ill post it up in the other section.
cheers benno