Is it easier for other sizes, or equally as difficult.

Equally as difficult, except for very small ones that go on a table - these are more of a decorative item than a bucket. Enamel in general has gotten somewhat rare. I found one (!) factory in Germany that does these. One.

Edit: I just checked:10l is max. There are no bigger ones and now I wonder why :)

	▲	svilen_dobrev 2 hours ago \| parent \| next [-]
		searching for "емайлирани съдове" in bulgarian.. https://elcishop.com/product-category/емайлирани-съдове/ https://www.mira-n.net/emailirani_rom_black.html https://zana-bg.com/kuhnya/sdove-za-gotvene/emajlirani/kupro... so 16L - and 50L - pots do exist.. but you have to find some importer around you. Manufacturers Seems russian, romanian, bulgarian..
	▲	loopback_device 4 hours ago \| parent \| prev [-]
		In case you haven't found it yet; have a look on https://emaille24.de/ - they do have buckets up to 12l (with lids).