Being inspired by this thread I think I should show you my newly installed darkroom as it is nearly finished.
It's an L-shaped room of 10mē in the basement of our home. The width of the wings - about 4m in length each - is 1.40m and 1.70m.
Obviously the most sophisticated part is the ventilation. It is sucking the air right above the trays, an idea discussed some time ago in one of the threads in this forum. It's very quiet thanks to the silencer built into the duct and the ventilator running in a silencing box. It is changing the air in the room ten times an hour if it is running at full speed. So it should be sufficient for working with selenium toner and other hazardous chemicals showing up in the future.
The tray table and the two large sinks I purchased for little money from professionals closing down their darkrooms.
My enlarger is a Dunco II66 with Ilford VC module sufficient for 35mm and MF. I'd prefer to have an L1200 though :-).

cheers

Ulrich