Connecting multiple display devices with different resolutions and hot swapping

[mnm]

Hi

I have a PC connected to an LCD (correctly overscanned res of 1216*684) and a projector (much more forgiving and happily takes assorted 720p modes). Only one display device is active at any one time via the same DVI port as the cable (with DVI-HDMI adaptor) is connected to a 1 in 2 out hdmi switch sending the signal to either the LCD or the PJ.

What I would like to do is switch between my 684 line & 720 line resolutions without changing any xorg config or restarting anything, just simple mode/resolution switches. This is a problem that feels like I have all the tools to do it but I just cannot see how nor can I think of appropriate search terms to narrow down the results

At present I just list all the modes for a single device and then switch between them using ctrl + alt + +/-. The result is that I get a virtual screen size of 1280*720 and all other resolutions are displayed within that screen size.

Is it possible to do what I want? if so, advice welcome.

Section "Monitor"
        Identifier      "Monitor0"
        VendorName      "Panasonic"        ModelName            "32in HDTV"
        HorizSync       15.0-70.0
        VertRefresh     48.0-61.0
        #DisplaySize    700 394
        Option          "DPI"                   "91x89"
        Mode "1216x684p60" 
                DotClock 74.160
                HTimings 1216 1356 1396 1648 
                VTimings 684 707 712 750  
                Flags "+hsync" "+vsync"
        EndMode
        Mode "1216x684p50" 
                DotClock 61.800
                HTimings 1216 1356 1396 1648 
                VTimings 684 707 712 750  
                Flags "+hsync" "+vsync"
        EndMode
        Mode "1280x720_72"
                DotClock 91.6144
                HTimings 1280 1352 1488 1696
                VTimings 720 723 750 751
                Flags "+hsync" "+vsync"
        EndMode
        Mode "1280x720_48"
                DotClock 61.076
                HTimings 1280 1352 1488 1696
                VTimings 720 723 750 751
                Flags "+hsync" "+vsync"
        EndMode
EndSection
Section "Device"
        Identifier      "NVIDIA Corporation NV45 [GeForce 6800GT]"
        Driver          "nvidia"
        BusID           "PCI:2:0:0"
        Option          "UseDisplayDevice"      "DFP"
        Option          "FlatPanelProperties"   "Scaling = native"
        Option          "IgnoreDisplayDevices"  "TV, CRT"
        Option          "ExactModeTimingsDVI"   "1"
        Option          "NoLogo"                "1"
        Option          "UseEDIDDpi"            "0"
        Option          "UseEDIDFreqs"          "0"
        Option          "NvAGP"                 "3"
        Option          "ModeValidation"        "AllowNon60HzDFPModes,NoEdidMaxPClkCheck,NoVertRefreshCheck,NoHorizSyncCheck,NoDFPNativeResolutionCheck,NoVesaModes,NoPredefinedModes,NoMaxPClkCheck"
EndSection
Section "Screen"
        Identifier      "Default Screen"
        Device          "NVIDIA Corporation NV45 [GeForce6800GT]"
        Monitor         "Monitor0"
        DefaultDepth    24
        SubSection "Display"
                Depth           24
                Modes           "1216x684p60" "1216x684p50" "1280x720_50" "1280x720_60" "1280x720_48" 
        EndSubSection
EndSection

Section "ServerLayout"
        Identifier      "Default Layout"
        Screen          "Default Screen"
        InputDevice     "Generic Keyboard"
        InputDevice     "Configured Mouse"
EndSection

Cheers
Matt