I think the old Fujitsu Lifebooks with the ~16:9 screen size and the nearly full sized keys is probably about the size you want on one of these things.
If I'm standing in front of a rack, plugged into another box—which is the primary purpose of this little guy—I'm gonna be holding it with one hand and typing with the other.
In that scenario, I'd rather have a keyboard of this size than a full-size one.
I think the old Fujitsu Lifebooks with the ~16:9 screen size and the nearly full sized keys is probably about the size you want on one of these things.