I really hope that high-end armor doesn't have to look as fancy as Elven, Daedric or Glass armor.

All of the high-end armor and weaponry in Morrowind and Oblivion looked rather ridiculous, at least when you're wearing a full set of it.

IMO Glass armour without the helmet in Morrowind was okay, but in Oblivion it looked sort of super-heroic. Ebony armour in Oblivion was awesome though. If only the Dovahkiin trailer armour was a high-end armour...but I don't think it will be.

The rarer the better (until you go into the extreme) i really loved the feeling of these 'impossible' to find armor sets. I really want to have to search for Ebony, Daedric, etc for weeks before finding a full set.

Exactly! That's also how it is constructed using the mod Morrowind Crafting by Drac & Toccatta.

Skyirm is set approximately 200 years since Vvardenfell was devastated by Red Mountain's eruption. Surely that's time enough for the island's infrastructure and mining industry to be reinstalled, possibly by the conquering Argonians who would be eager to reap their new land's spoils of ebony and glass. Also consider that volcanic ash is brilliantly fertile and responsible for much of Vvardenfell's lusher regions, by this point the island would be a land rich with vegetation to support a thriving mining industry.

This said, that doesn't mean glass and ebony artefacts should be common by any means. They should be a sign of real status on certain NPCs or a sign a skill and hard work on the PC.