You can use a 12 port patch panel, or a double gang plate... and if you want to put a lock box -- you have a few options. The alarm ones (at least that I've seen) are fairly large, in the 12"x12" department, maybe some slightly smaller -- but all far too large for a double gang box.
I think your best bet would be to modify a key storage box that property management/hotels/real estate agents use. They make smaller ones that are about perfect size, MMF industries makes several varities, one I believe is 7x7x2.5" which would be PERFECT. You could put a grommet at the bottom for patch cords to exit, and cut out the back but leave a 1" or so edge to attach your screws to.
Their key boxes look like this:
https://www.mmfind.com/keycontr.htm Might try that... I can't think of a comercially available product that does that, although I'm sure there is somewhere.
