Another option that has not been suggested is to grind off the pointy parts on the back of a trouser belt buckle and solder onto the waistplate of a Kilt Belt.

Simply use a plain waistplate to start with. Anyone with any experience soldering jewelry should be able to do this for you.

Remember to use silver solder and not the type used for electrical work. Also avoid epoxy. Both of these methods will result in you buckle popping off and being lost or damaged.