no room for you - it's only 3 to 4 inches deep - I think it's a air duct for the floor heater - it "is" enough space to mount a Radio control head or siren controller which I have seen in Police versions of the '05 xterra (the hidden strobe kit looks really cool on the "X") - - to get an idea on how deep it is, on xterra's that don't have VDC or any other switches, there is a storage hole next to the 4x4 dial - it extends in to the maximum depth.
Switch Assembly Bracket and Center Console Pocket I tried and failed to mount a little CB radio in the upper glove box - cut a hole in the back of it as a pass through - was about 2 inches off (only measured one, and yes, I know better)
Side Note; If you wanted to add switches, these marine switches fit great into the blanks to the left of the steering wheel and blanks under the HVAC controls -
Water Resistant Contura Switch-Black