I really am not trying to highjack this thread, but thought I would bring this to your attention. I was at a gun show last week and saw this neat knife sharpener, called the Warthog. It is made in South Africa and looks to be well built, if not slightly funny looking. It is easy to use, but is on the expensive side and it is not really field-use friendly, but may serve for home use. Here are a few web sites, if you are interested, the vendor at the gun show, was a US distributor, so I would believe it is available elsewhere.
Pete
Warthog web site Warthog US Warthog Review