i've read about people improving weapons and armor past legendary status. my smithing skill is at 100, and i have all the smithing perks (except for smithing glass armor, but it's heavy daedric armor i'm trying to improve), but when i try to improve my legendary armor/weapons, it says something along the lines of "you don't have the skill requiered to do this".
i've tried it at both a regular blacksmithing area, and the skyforge after completing the companions questline.
I don't know if it will un-grey the item, but what they're referring to is using a bunch of Fortify Smithing potions and armor in order to squeeze a few extra points of armor/damage out of the upgrade.
There's no status past Legendary, however you can still improve the quality of the item if you get your Smithing skill high enough to do so. Enchant a ring, necklace, gauntlets and an armor with fortify blacksmithing and drink a fortify blacksmithing potion! Hope this helps. :)
If you use the fortify restoration glitch you can get things well past what they would normally have at smithing 100, but they will still say legendary.
On my first playthrough I think my deadric bow did about 120 damage with 100 smithing.
On my second (completely broken) playthrough I have a ring that improves smithing something like 128,000%, and my bow dows about 428,000 damage. Even though it only displays the first three digits, you can see it in the items screen that it is actually about 428k.
Again no arguments about cheating, it's my game after all.
Without glitching and just high alchemy, and enchanting a set of +20 to smithing you can still max about +250% smithing I think.
"The Miss Universe Pageant is fixed, the winners are always from Earth."