they make that b-17 in a Narrow, which i believe is as narow as any brooks saddle. even their narrow is wide compared to most racing type saddles, especially in the most rearward portion of the saddle.
i think the narrow is close to the b17 in price, or maybe the same.
the best prices for brooks that i have seen are nashbar on sale, and wallbike. as stated above, i recc. wallbike for their no-questions asked return policy. you just can't beat that. maybe wallbike has a used brooks for sale at discount.