Well, I have managed to sort of force a DUXA-style gauge into my QQUI, just copied only the WindowPieces01.tga file from Duxa into my QQUI. It accomplishes what I wanted with a few minor side-effects of odd looking, not-as-transparent velious-UI style window edges, and textures in weird places etc.
It's not exactly what I was hoping, but I think for my needs it suits me for now.
Side-by-side comparison pic attached:
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I hope maybe someone else out there would like to see a real addition of this added to the QQUI in the future! Thanks to Duxa, Cucs, Crookstinger, Beezertwelve, and anyone else who has helped this awesome UI along the way!