The height requirement for any airline operating aircraft B737 size or larger is a joke... its from older times when aircraft had TV's hanging down in the aisle, but they are just about all gone now - except the possibility of some of QF's B734's I think...
I am unsure if Jetstar have a height limit, however Virgin Blue definately doesn't - there are some fairly tall crew flying for DJ. So long as you can run through a dark smoke filled cabin without hitting your head on the roof I think you will be ok
PS You don't actually need to run through a smoke filled cabin to get the job, but obviously in a fire/evac you would!