How to create an own keyboard model?
my keyboard requires an own keycode cfg and I am using an own variant.
setxkbmap -model pc104 -keycodes fslgs -layout de -variant elm

However I need to create an own model comprising the fslgs keycodes because otherwise I will not be able to switch between keyboard layouts with kcontrol/KDE.

I have googled a lot but found no useful information about it.

Since nobody has answered, I thought I ought to say something. I suspect the problem is that nobody can understand your post. I can't, and I always thought I was rather an expert on keyboards! You need to explain exactly what you have done, what you are trying to do, and where you found a problem.

For example,

What is fslgs?
If your keyboard is is a pc 104, why does it not use standard pc scancodes?
If you are using the keyboard with your own keycode file and customised German layout, what is it that you are still trying to create?
Where's the problem with switching and which layouts are you switching between?

Look for X11/xkb/symbols dir. I also can't understand exactly your questions, but you can define keyboard layouts and models from there.

Basically I just wanna define my own keyboard model; i.e. something that can be activated by setxkbmap -model my-fslgs-model.
The thing about it is that my keyboard requires the adjustment of certain scan-codes which is currently done by the fslgs-keycodes table in /usr/share/X11/xkb/keycodes/fslgs. However KDE does not allow me to specify my own keycode table. It only allows to change the keyboard model so that I need to define a keyboard model which comprises my fslgs-scancode adjustments.