[xmonad] xinerama and per-screen automatic layout modification

Hi, I'm using xmonad with two equally-sized screens the left one of which I sometimes turn into pivot mode (rotate 90°) to read articles. Now 'Tall' isn't great on a portrait monitor, so I'm looking for a layout modifier that acts as follows: * If on the right monitor: No modification * If on the left monitor: o If in pivot mode, apply the Mirror layout modifier. o Otherwise, apply the Reflect layout modifier. (because I like my master windows in the center) Has anybody worked on something like this before? If not, I'd try to write a contrib module, probably re-using some code from Actions.PhysicalScreens. Any pointers / pitfalls to be expected? kthx. Best, Steffen