to borrow from a common idea, the "commo-rose"
http://spartanwarfighters.net/2top/3forum/images/PR/v90/PR_SL_commo_rose.png

I'd like not only mouse movements to be able to select, but also the ability to have WASD (and QEZC) select various menu entries as well.

upvoted, especially

1. Pressing B equips binoculars, doesn't use them.
2. LMB+wheel adjusts zoom

(or whichever key is bound to zoom+/-)

dare we suggest implementing head-related transform functions?
http://en.wikipedia.org/wiki/Head-related_transfer_function

Mousewheel is still digital (usually),
I would suggest instead for completely analog control, use MODIFIER+MOUSE
like CTRL+MOUSE

it would be similar to the old Half-Life engine's "strafe modifier" key, when pressed, moving the mouse left/right allowed you to adjust your left/right position to arbitrary fluidity. This could work in all directions (up/down, left/right) with the only disadv. being temporarily loss of mouse to control aiming, but the adv. of being to able to set any stance with 2 degrees of freedom (x and y). Optionally, another modifier can be used to control z stance adjustment so we don't have to do silly things like crouch-walk just to inch a little bit forward- just hold modifier and move the mouse forward;

the detonators should be a physical item in your inventory that are picked up with the explosives and replaced with the explosives after they have been planted.

depending on the explosive complexity, you can have either 1:1 detonator:explosive, or a single detonator to multiple explosives that can have its frequency/range adjusted (similar to ACE radios)

+1

a solution might be:
press v to vault
hold v to begin climb/mount (of face-level or lower surface)

using a hold bind would prevent it from becoming a canned animation sequence, this way it can be easily triggered and just as easily cancelled mid-climb.