Willis Duct Expansion

Willis Ducts are an incredibly useful addition, providing a compact and four-sides airtight - if cramped - maintenance access solution. Despite being intended as maintenance ducts, however, they don't have any access panel or even door variants! I propose the following Willis Duct additions to make them useful in their intended role:

• Willis Duct Bulkhead: A duct with an integrated door, to more easily allow sections to be sealed off with an airtight bulkhead.
• Willis Duct Access Panel: Simply a duct with an integrated access panel, for accessing the grid terminal. An additional variant with an integrated button panel, or even a single button, would be even better, and allow for duct-based airlock systems.
• Willis Duct Air Vent: Not to be confused with the existing duct with the small air grating, this duct would have an integrated air vent in its base and a conveyor port on its bottom, allowing both maintenance traversal and an air supply in the same block. Also handy for duct airlocks.

For flavour, I'd also like to suggest a duct variant with a top opening, and an additional grating block to place over it - currently, we can only enter ducts from the side, but this would open up floor and ceiling access like in many of our favourite sci-fi horrors. Remember to look up next time you're boarding that dead ship. :)