Mick touched on it before, but I can tell you for certain that Botswana has 50hrs ICUS.
That terrain there is perfectly flat with weather conditions very similar to northern aussie.
You are being taught a totally different style of flying than what you are used to from flight school. In fact, it involves throwing some of the stuff you learnt there out the window.
By the end of those 50hrs you are very proficient at what you are doing and are expected to be able to navigate around by terrain features with a failed GPS, landing with tailwinds, thunderstorm navigation, traffic and bird awareness (There is roughly 70 aircraft operating to an area within 80nm of the main airport) and general bush flying techniques.
Personally, I don't see anything wrong with 50hrs ICUS. Can be done easily in 3 weeks.