If you get the smithing perk to smith ebony weapons and armor you cant buy ebony ore. You have to get daedric smithing perk to be able to buy it. Which makes ebony armor and weapons smithing useless. Unless you don't care if its the strongest armor or not.

humm i can say with 100% certainty i didn't have that problem i only recently got ebony smithing and i had to buy a few ebony ingots and ore to make my amour. had no problem other than cash .

Same here, never had this problem, forges dont always have it available but Whiterun is usually pretty good for 10 ingots every couple of days.

Well you can also mine the ore. There are a few good places to get it.

I had no big trouble finding it from merchants either. But you do have to shop around sometimes.

Well this was pre- 1.4 so maybe it was fixed. But the problem is gone now.

Ebony Ore seems to be hard to come by, I don't think I've even come across a single piece of ebony ore.

I always thought the type of materials that appear depend on your smithing level. When I took the glass armor perk, the materials to make a full set of armor + shield + sword were very hard to come by, I had to hop from town to town numerous times to get all the materials to make the armor. Once I hit 100 in smithing and took all the perks I began to see every town having all the materials, or at least all of the available ingots. Whiterun for example usually has at least 10 of each ingot now. It could have been a pre 1.4 thing, since I didn't get 100 in smithing until after 1.4. But even after downloading 1.4 I still couldn't find all the available ingots, until I hit 100.

It could be sth like how weapons work? Enemies always drop better than the vendors have. Maybe the supplies are supposed to be more rare from vendors until you are a tick or two above the minimum level.