So ive decided i wana collect all the masks and get my hands on the final mask but early on in the game i aquired 1 (volsung i think) but sold it to a merchant cus it was just sitting there collecting dust and i needed the cash.

Im pretty sure i can remember selling it to warmaidens but it was very early on and they will have restocked 100 times since then so i assumed its lost forever. I know its very unlikely but is there anyway to get this mask back?

IF you are on the PC => Check for consoles

This. If you're on Xbox or PS3, you're screwed.

360. Screwed. Damn it

Sorry to hear that, better luck next time.

If that is really the case, that is too bad. You would think for unique items that they would be locked in some way, wherever they are at any particular moment. For example in Warmaiden's stock, if you sell them unique items or items with a proper name (Bolar's Oathblade), then it should re-stock but also leave those unique items permanently in there so you can always buy them back later if you need them for whatever reason.

Further to this, how cool would it be to sell someone this type of item, go back for it and get a dialogue along the lines of, "Thanks again for selling me that dragon mask. Mikael, that Bard over in The Bannered Mare, paid me a nice sum of gold for that trinket." Then you get a miscellaneous task to get the mask back from Mikael. When you show up to The Bannered Mare, there is Mikael wearing the mask. You can then either pickpocket him, bribe him for it, fist fight him for it, or kill him for it.

I think having these types of items move around in the game and generate appropriate dialogue and sometimes a small side quest or task would add so much more depth to the world.

I also wish they had a special container for all the dragon claws and dragon masks, being that they are fairly prominent and unique to Skyrim.

Yet another accident that could have been prevented if you were a member of the master race *dusts off shoulder*

Even in Morrowind if you sold a merchant a good piece of armor or clothing, you couldn't get it back without console commands. I remember I once sold a daedric helm to the armorer in Mournhold and she instantly equipped it, leaving me unable to buy it back.

I think you should pose the question about masks to Pete Hines. I'd bet he's developed a whole closet full of masks he uses in daily life the past 2-3 weeks. Likely cloaked with invisibility potions. However, we know those potions tend to wear out over time.

Or if you had some sense and did not sell off named items.
Hoard, hoard and thrice hoard.

The true master uses the Way of the Squirrel.

This is true, I now just store named items or things that I think might be important. There are so many other ways to make gold it's not worth selling off the rare items.