Not sure how hard it would be to create. Maybe im dreaming but:
/settrap
check if player has c4 - no c4 = exit
player has atleast 1 c4 - consume c4 and place invisible marker on map x,y,z with radius of whatever the c4 death range is 1-2 meters perhaps?
checks for any player (maybe anyone but the player who set command) entering that radius then -
spawn a c4 on that location (best with short fuse but probably impossible) then delete trigger.
Fun ? I think yes!
