Willem,
I went through Carport Central to quote my building, which is 22x36.
http://www.carportcentral.com/product-category/garage/vertical-roof-style/
The manufacturer that was closest to my location (Carolina Carports, Dobson, NC) did the install after I had my lot graded and concrete poured. The installation was completed in a day and a half.
They went through the different options with me. I did a vertical roof, meaning the ribs run from eave to peak. I also went with a certified building (not required for my city/county codes), designed to withstand higher winds and snow loads, by placing the posts and beams closer to each other and more fasteners into the concrete slab. When I bought mine in late 2016, it was less than $500 to add this to the cost of the building.
I have two 9' rollup doors, one in one end, and the other along the long side wall near the back of the building. I also have 2 walk-in doors on the same side as one of the rollup doors.
After I have the initial electrical panel installed by a licensed contractor (and subsequent inspection), i did the remainder of the wiring myself, using 12/3 armored cable. that was easier than running PVC/EMT conduit, but probably wound up being more expensive.
One thing that I was not prepared for was the amount of rain water that came off of the room, even with a light rain. I constantly had problems with water seeping under the side garage door, no matter how may times i reset the rubber door sill under the door. I eventually put gutters on the side with the doors and that has eliminated 99% of my rain issue. On days where snow stays on the roof, the melted snow will not flow into the gutter, so I usually go out and rake the snow off of the roof.
My building is not insulated, so be prepared for extreme cold and heat. I have a small electric heater to warm the area where I am most often working, but it cannot keep up with the recent cold days we have had lately. In the summer, I open all doors and I have a ceiling fan installed to move the air around, and it can reach in excess of 120 when closed up. When the sun directly hits the building, you will not be able to hold your hand on the metal siding. I am strongly considering the SolarPanel plywood panels to reflect some of this radiant heat. I will admit that it does feel good in the winter time, until the sun starts setting.
I have to use the metal drilling screws to mount anything to the metal posts, and since my posts are not on 4' centers, firing strips will be needed to hang plywood on the walls.
I had to have grading done, as there was a 40" slope across the diagonals of the building. This grading and concrete for me was around $3k, with $7k in the building. I could have gotten a wooden building for the same price, but less than half of the space.
Would I do it again, yes. I wanted to go a little larger, but I had other limitations surrounding me.
Hope this helps. If there are questions that I didn't answer, let me know, I'll answer as best I can.