Originally Posted by Retro Grouch
Actually they are. Try buying one of the cables you have listed above that you think has two ends and post me back.
The only QBP shift cable that has two ends is their very cheapest generic cable. The others don't say they have two ends, they say that they will fit either road or mountain bikes. Shimano does market different cables labeled Dura Ace and XTR, but the ends pictured in the QBP catalogue sure look the same to me. Anyway, I've used up several file boxes of shift cables. They all have only the button end and I can't remember EVER needing a shift cable with a barrel end.
I have about 2 dozen of the double ended type and have used the 'non typical' end on something. I misread the listing for brake cables in the qbp, and nearly all relatively recent mtb shifters also use the typical road style head.