It's not located in the D concourse, but the old Crown Room is now an America West Club. I missed a flight last winter and had a seven hour wait, so it was worth the $35.00/day fee to use it. For those that have the "Priority Pass", it would also allow use of the America West Club the last time I checked.
I'm not sure if the National Club has a daily fee or not, but if you have a long layover it might be worth it to use.