Mariner Sails is found in Dallas. He has a brick and mortar store as well as being on-line. Their store has an amazing assortment of accessories on the floor. If you order on-line, I am sure you will get what you order quickly since they will not have to order it in.
This store has a great selection of accessories and kayaks. The sales staff seemed to be quite knowledgeable. The gentleman I talked to said they get you get pretty much anything you want and ship it to you.
PS: If you like the show "Fast and Loud," Grease Monkey Garage is only five minutes away.