I have been searching for hours and have only found some free laying around. And I sold some early on not realizing how rare they were. Now I have smithing 80 and the perk, but only 4 ebony ingots to use.

Any advice?

Oh, and do ore reserves replenish in the rocks eventually?

theres an orcish camp connected to an ebony mine... I believe they are supposed to but for me they reappear and are unmineable

Yeah it's the best mine 20 min down there.. 48 ores ^^

And at higher levels(20 or so) general stores and blacksmiths will start to sell ingots. These however are quite expensive.

I believe the default cell respawn rate is 30 game days, that would be the maximum amount of time you'd need to wait.

This would also respawn any vendors that have Ebony Ingots laying around in their store for you to steal.

The Orc camp in the east is the best, skirt around the city, enter mine, take what you can. They even send out thugs to attack you randomly for taking their ore which is always fun. Do this way before you need it so after 30 days game time it respawns and you have enough for you and your companion if you need. Orcs telling Nords that this land is the orcs and calling Nords oulanders in their own land is reason enough to take what you want from them and slaughter them anyway.

OMG so funny, I get them the gloves they wanted and a dragon comes along and kills every last one of them before I could take it down. I walked over to the dead body and took back those gloves for free, lol.