I completely understand.
In that case, I'll second the notion (Neal beat me to it) for a Queen or Schatt & Morgan Railsplitter depending on which blade steel you prefer. (D2 or 420HC) There were also some Tuna Valley Railsplitters made with 154CM steel. One thing to note about the late model Queen Railsplitters is that they have a nice Pen blade in place of the Spey blade. I believe the Tuna Valley's have this same feature but I'm not sure. Maybe not for everybody but I think it's a nice change of pace.
I like the Railsplitter pattern primarily because the handle is chunky for a 3 5/8 inch knife. While not officially called a Stockman, the three blade Railsplitters are basically a Stockman with a fat handle and often overlooked when considering a Stockman because they don't carry that name.
Please let us know what you decide on if the mood should strike you. Good luck. I hope whatever you choose, your Father adores it.