Thank you for helping me!
I played around a few hours today using a midi keyboard with eight pads. Tried setting up combinations for those and realized i need four pads per track. That was excluding the undo.
I found the combination functions for record or overdub. However, is there any way to erase a loop which has been recorded, or force it to start over again? I mean, after a record has been created, I need to press the gui record button if I want to do another recording that is not just an overdub.
The FCB1010 is not too big. I like it when I have a chance hitting the buttons.

Yes, I have considered the bank switching feature. Trying to picture the workflow. I'm very new to looping in general but I realize that page browsing will add up complexity. Can't tell if it is an issue or not.
I haven't played with the Boss RC 300 for instance, but that beast only have two buttons for each loop plus one global, and from what I can see on youtube people can control it quite well. Is Sooperlooper configurable to mimic the RC 300? I don't know if it would even be desirable, but if I knew that I at least can use the FCB1010 as I could use an RC 300 would help me decide.
If I really need five buttons per loop, I might end up building myself a matrix of arcade buttons and some microcontroller based midi interface. Though I don't believe I can come even close to the quality of the FCB1010.