As a UK owner I have my version of what the Utilikilt is.
The kilt is originally a garment from the United Kingdom. Hopefully, to be more accurate, it is more Scots and Irish I believe. The Utilikilt has taken the kilt and redesigned its pattern into an american adaptation for easier recognition and acceptance in America as a man's garment for american men. Then all men locally and abroad. In that effort the usual clan tartan has been eliminated and replaced with cloth that is non clan and non tartan and made/woven in America.
The Utilikilt is in essence, "Son of Kilt." Likewise, are all the other american made kilts made in american cloth of non tartan weave. Many kilts are made outside of america and The U.K. with a variety of cloths. Those might be seen as second cousins or whatever, to the kilt. Not american, but related by pattern and intend uses. Of course, the kilts made in america of U.K. tartans are "Brother of Kilt."
I think I'm digging a hole for myself here. At any rate, the UK is an american's adaptation to the Scots/Irish kilt.