well, here in River City...several courses already have, and they're probably going to go to this on all of the courses, the unused placements have a sprinkler head cover. The placement in use has one cut so the pole can go through it. It makes sense, the mowers go right over the covers and the pipes aren't exposed.
I'm not sure of the expense involved, but it works here.
As far as height goes, to me that's a non-issue. Maybe the manufacturers need to have 2 holes drilled for locks, one high and one low. That way a raised sleeve or sub-surface sleeve could be used.