The problem is the individual persons personal definition of what a "big hill" really is...Just because there are hills doesn't mean you need triple chain ring up front and a 9-10 speed cassette in the rear. Most areas with rolling terrain can be ridden with a single gear.
I've never ridden an IGH bike because I prefer FG/SS but I bet a 3 speed IGH with three gear ratios would be perfect for most situations. Do you really need 27 gears ??