Auto on/off case??

Not entirely sure what you are referring to - are you referring to a case that comes on and off automatically or one that switches phone on and off.

If re switching phone on and off really don't see the point of that due to boot up times etc, though there is the fast boot option though this can cause issues. Sony is starting to work on this sort of stuff via NFC - use a smart tag which you can put in office, home etc, as phone passes it will switch profiles as per the NFC tag and how you have set it up. Should work for any phone. So its possible, though I have never seen one.

Be careful of magnetic cases as these can cause issues - Dock Nothingness can help assist with the issues these cases cause.

Not aware of any, though I believe its possible for blackberry etc. I have heard where magnetic cases can cause the dock app to launch etc, and as i have said you could set up a profile and use a sony NFC tag to do the job.

However have you considered the automatic time off? Settings -- > display --> Screen timeout. If you set it to around a minute I think you will generally find that it stays on long enough that its unlikely to annoy you by blacking out while doing stuff yet it goes off quick enough it shouldn't launch something when you put it in a case. If you tie it together with a lock screen that only goes on after say 3 minutes of inactivity (i.e. screen off) it makes quite a nice combination. You can also twin that with apps that will wake up the phone using any button (some also can do it via a screen but these will consume more battery).

Thanks guys. I'll work through those hints and any others that pop up.