The main shopping streets are Talaa Kebira and Talaa Seghira, which converge near the bottom of the slope, close to the qisarriat, the covered market area that stocks more workaday products, such as fabrics and phones. If you see something you like, either buy it or drop a GPS pin so you can find your way back.
If you'll be in Fez for the better part of a week, you have time to order a custom-tailored djellaba or caftan – just as Moroccan women do (it's less common for men, but still possible). First visit the kissariat for fabric; if you say it's for a djellaba, the shopkeeper will cut you the requisite 2.5m. If you see trim you like, buy that too – though tailors do stock it. Then take it all to a tailor for an initial fitting. Machine sewing costs about Dh200, and turnaround takes between four and seven days. Hand-sewn work is double in both price and time. Abdelbaki Elaouni, near Ain Azleten, comes recommended, but there are small tailor shops (always men) dotted all over the medina.