The Crunch bag is good quality, but holds a little less than what you said you were looking for. It's better for 10-15 discs, not 15-20. A lot of people carrying 15-20 discs use the Innova Competition bag, which is what I sell the most of. I currently have the comp bag in stock. I think I'm actually cheaper than most of the Amazon sellers too at $46.
Aces and Chains
1706 W. Jefferson St.
Right behind the Subway.
Sorry for the shameless plug guys.....