is there a console command to tick/untick the "use 360 controller" menu item? Or a way to have a reasonable facsimile...

I'm not sure I understand the question. The menu settings is the only way to toggle the controller / KB&M.

the question was whether or not there is a console command that would do the same thing as checking that box. surfing thru the menus to find the tick takes a lot longer than using the console and i have a need (making video) to switch regularly.

If the switch is enabled, just simply connecting/disconnecting the controller will have the same effect.

That actually didn't work for me. Not surprising, it sounds like one of those "depending on your setup" things.

What I did find was "http://skyrim.nexusmods.com/mods/27914" mod. An exe isn't the optimal, but it's from a known mod team and it's a simple in game trainer that works exactly as advertised... and fit the bill quite nicely.