After a few tests with walking, I decided to not give it a huge head after all. I tried a number of different heads (including several acrylic globes from a crafts store, a doll's head and a lightbulb) and finally settled on a cardboard outline. This is something that an 11-years old can see and say "I could do that!"
For now I used the same code for walking as the #Micro:Bob (I just had to swap some pins and adjust trims), but I want to make it controlled from a second Micro:bit.
So this is a successor of the #Micro:Bob robot, that would be a little less "gangsta". I designed a PCB for attaching everything together -- the micro:bit, the servos and the battery -- so that you don't have an ungodly mess of wires held together with two-sided tape. I also left some extra holes in the PCB to which you can solder paperclips, to build on top of it and make it a little more interesting.
I found a nice method of mounting the micro:bit to the PCB without using the bulky edge connection -- just use loops of wire made out of paperclips, and plastic bolts (to not damage the micro:bit). The servos fit right into the slots -- I just made the screw holes a bit too tight, had to enlarge them a bit later. The battery holder is still attached to the backs of the servos with a two-sided tape -- there is no room on the board for a different way of attaching it, unfortunately.
In hindsight, I should have made more sockets for the servos -- letting you to plug several servos to the same pin, so they move together, so that you can make hands that move together with the legs, etc. -- maybe in the next version.