Jesper, I will take some photos of the brackets tonight so you can see which ones I am using. They are the "double" type brackets, very strong, but unfortunately also expensive.
They come in several sizes, 6", 9", 11.5", 14", 18", and 24" at my Home Depot. The 18" brackets are around $5 each, the 24" ones are around $7. The bracket track which attaches to the wall is not all that cheap either. Still, I am happy with the set-up, I feel the ease of installation was worth the cost.
One issue with the 18 inch and 24 inch brackets is that they have a built in slope up from back to front. There are several ways to overcome this, something we were discussing a couple months ago here at The Gauge. One way to level the benchwork woud be to put a "leveling nut and bolt" on the bracket. Another option is to file down the lower portion of the bracket where it goes against the track, I did this for about one fourth of the brackets until I found a quicker solution. What I ended up doing was simply putting my weight on the front of the bracket and carefully pulling down in tiny increments until the bracket is level. What this does is slightly bend the track. If you go too far, the track can be bent back out with a screw-driver. One thing though, the track has to be very securely attached to the studs in the wall to use this method of leveling. I used 3" coarse thread drywall screws, 4 per track. I drilled extra holes in the tracks where needed, mostly right at the very top where the bracket attaches.
This method is crude, but it is effective. Perhaps the filing method is the best though.