BTW you can get a FIXED wheel internally geared hub, its a colectors item by Sturmey Archer, found of high-end custom English racing bikes of the 1930s.
Do you mean you have a choice of different gear ratios but it would still be fixed (stop by backpedaling)?
I did not know something like this existed. Why doesn't someone currently make somthing like this? A fixed gear with three different ratios would be the ultimate for hilly areas.