In the meantime this is now possible by using the new geometry feature:
way({{bbox}})[building];
out geom meta 10;
It will display exactly 10 buildings.
Note that there's a small rendering issue in overpass turbo (or more specifically the osmtogeojson library) at this time, as only the boundary box is shown. However, as the new geometry feature is only available since a few days, rather new, I'm sure the rendering will be ok pretty soon. This has no impact on the query itself, though.
Try on Overpass Turbo: [http://overpass-turbo.eu/s/50g][1]
[1]: http://overpass-turbo.eu/s/50g