@kexe 
oh my god that sounds so fun. If you really make that one let me know lol.
Its basically a 3-tiered skirt with a bunch of panels of your liking on top I found in a lolita-sewing magazine and fell in love with. I needed that skirt in my life. (luckily I found a pattern service which has these as printable patterns). Even bought a printer (I needed one anyway mostly for scanning stuff and printing the occasional document)
Very fun indeed. Your Trasflag idea might work very well. Kinda reminds me of that image and flag someone on here posted where they took the bavarian flag and gave it transcolors. Sadly I dunno who posted that one. But with rhombus panels instead of normal rectangles we might be onto something. Though sewing those one would be kinda difficult