The only one you need to know about is Challenger-N-scale. Richard Fisher is the proprietor and an acquaintance of mine. The club that is done out of his shop is ntrak and he has setup a small loop in the shop. He has a great selection too. Here is the not oft updated website: http://www.challenger-n-scale.com/index2.html
Yes except for Saturday which he closes at 6. On some of the weekdays, a man with glasses named Ricky runs the shop for Richard since Richard is still full time with another job.
Great shop and very friendly people, went there during a business trip and was very happy to find this shop, highly recommended.