There is a B17N. the N stands for Narrow. It is more for a bike that keeps you in more of a racing position or if you have a skinny Butt.
I have a Champion Flyer (B17 with spring suspension) on my T700. Love it!
It did take a good 500 miles to really start to conform to my behind. At nearly 2,000 miles It now is more comfortable without riding shorts then any of my other saddles are with shorts. Top of the list for one of the best bike related items I have ever bought.