This is a bit of an obvious suggestion, but also I suspect a bit tricky.

I'd like to propose an add-on kit for the Fyrburgh towers that add a level of height. This would allow for towers of different heights (you could even stack extensions) and would make making a guardhouse out of existing bits easier.

To make things easy a level would be the height of the current interior walls (half the exterior height). I suggest that it should have an arrowslit in three of its walls, and a trapdoor hatch adjacent to the last wall for a ladder (not central, so as to avoid clashing with the flighting-platform ladder hatch).

The difficulty would be, I suspect, the existing brackets on the towerbase to support the platform above; which would no longer be needed for this due to the intervening extra level. I can think of three 'solutions':-
  1. Carry forward this extra width as a 'flying buttress' up the height of the level
  2. Have an inverted bracket to nullify the support bracket below. If this was a 'modern' tower, I'd run a bit of barbed wire around these brackets to make a anti-climbing defense
  3. Make a decorated feature of the brackets by hanging-off shields, lion-heads, gargoyle etc

None of these are brilliant solutions. I prefer the last (3), and dislike the first (1) most. I am sure the eventive minds of 4Ground's designers will come up with a better solution.