What do I need to make a decent Ras-El-Hanout from scratch?

There are many recipes for ras el hanout on the web, but you could also find a recipe in a good Moroccan cookbook. Paula Wolfert is a reliable source. Ras el hanout recipes vary--every spice shop has its own blend and secret ingredients, so it is a recipe you can play around with and make to suit your tastes.

Here's one from Kitty Morse in The Scent of Orange Blossoms, a lovely book.
2 tsp gr allspice, 1 tsp gr nutmeg, 2 tsp gr mace, 1 tsp gr ginger, 1/4 tsp gr black pepper, 1/2 tsp salt, 1/2 tsp gr cinnamon. You can use toasted whole spices and grind them.
This should be wonderful on roasted veg. I'm thinking sweet potato....

Depending on your experience with REH , you have a wide range of spices to choose and blend to make this mix. Most I have tasted have cinnamon,clove,pepper,cumin,allspice,ginger,coriander,celery seed,fennel,and many other unknown spices added whimsically to the mix. it is a firey blend that is rarely the same twice...good luck !!!