Hi Shane,
That's a nice decorative pair. Double knives are found in various cultures.Some have interlocking hilts, similar to what you show, while others have two separate knives. If you search the Forum for double knives, you will find other examples. One place to start is this thread,
http://www.vikingsword.com/vb/showthread.php?t=29636, which shows several with interlocking hilts.
Ian.