Hi Wino,
A biltong cutter is a of stacked, bolted together pair of wooden blocks with a knife attached so that you get good leverage to cut the biltong. Asher got a biltong maker for his 40th birthday (custom made by a friend) and we bought a cutter when we were in SA. There isn't anyone currently making them in the US.
Here is an example. Ours is smaller and darker wood but is otherwise pretty close. You put the biltong on the smaller block and slice it with the knife.
There is much wine. We put out at least 30 empties. I always wonder what the recycling people think of us the day after this party.
--Lisa