Actually a basic support for this type of reservation is already in the making (current 2.3 development code).
Although right now there are no user-defined reservations, only for crouching/standing up (and for shooting to some extend, if you misuse the reaction-reservation for it).
I'm not sure how much I'll get done, but at least 2 things
may get implemented additional to reservations for crouching:
- Reservation for shooting (i.e. reserve a value from one of the firemodes of your weapons).
- Custom value (Enter your own value).
Both are currently lacking a good way to make them available to the player (i.e. no good GUI integration), but that may change in the future.
Werner