I had a buyout similar to this and the company put out instructions for the allocation of basis about a week after the close. Briefly, we were instructed to allocate a percentage of our original basis to the new shares and the remainder to the cash portion.
In this example we are using for Cappy, and using EPholders figures,it appears that the total of KMI shares and warrants is about half of the total value received. The cash recieved is about half of that total also.
So my guess is that 1/2 of Cappys original basis will be allocated to the cash and the rest split between the shares and the warrants, with the stock shares obviously taking the bulk of the allocation there.
If that happens, about half of his original basis will carry forward to the new shares and warrants and the other half to the taxable event of the cash received. I'm just rounding for discussion's sake. When we got instructions on my other buyout they issued exact percentages out to the hundreths.
I also hope for everyones sake that KMI issues clear instructions and doesn't chicken out with a "contact your own tax advisor" disclaimer.