I haven't gotten very far with my canopy yet but have been planning on building one myself out of aluminum diamond plate with the same sort of framework underneath, and a box of sorts dropping down in the front, framed out of the same tubing. I had envisioned closing in the bottom of this box with expanded sheet metal grating type material to make a compartment like what you are talking about. I wish I had a way to draw it out, it makes sense in my head at least. But I had a lot more plans to go along with it. It may seem silly all by itself. I have LED lightbars front and rear, so the front one will accompany this box, and I will probably also add a radio, fan, and "switch board" for all of these accessories beside this box. So it will be sort of a "console" across the front edge of the canopy, just behind the light bar that will line the very front edge of it.
Not sure if this helps, but maybe it will give you some sort of a visual idea to create your own