For curry spices, go right to the source (and ask the horse, LOL)
I like Lakshmi Foods at 8 Mile & Middlebelt (next to the Pepperidge Farm outlet) for all things Indian. Cheaper than Penzeys, IMO, for what you will find there. Awesome samosas too when they have them. (also can be combined with a Cantoro's Italian Market visit as they are right around the corner)
Penzeys does have a fantastic overall selection, not sure about "moroccan" though. But a worthy place to visit.
Plum Market, 15 & Lahser, might also be worth a shot.
This is an alternative to endless searches in the Detroit area. I've bought Ras el Hanout (listed ingredients on the bag: nutmeg, sea salt, black pepper, ginger, cardamom, mace, cinnamon, ground allspice, turmeric and saffron) online from the Savory Spice Shop, Inc. Okay, it's not a 25-ingredient blend like in Morocco's souks, but it's pretty good and very fresh. Visit www.savoryspiceshop.com online or call (303) 477-3322 or (720) 283-2232. The first number is in Denver and the second is Littleton, Colorado. They also have a number of interesting spice blends worth trying.