Hesantia wrote:So, if I'm getting this right, I will not be able to transmog the lvl 60 PvP gear, no matter if I buy it from Dmf or the vendors in orgrimmar/stormwind? (or were these sets moved to OL?) and I will not be able to transmog the weapons either? That really sucks, since my main is a draenei so I could never have gotten that achievment anyway... =/
The level 60 PvP gear (which is in SW/Org and Netherstorm) will not be transmoggable unless you had the appropriate rating back in vanilla, regardless of where you buy it from. I wish that label was applied to the gear somewhere; it's very confusing otherwise.
Hesantia wrote:Oh, and the newer sets, like the merciless gladiator (black rift stalker) will they be transmoggable?
Those are indeed transmoggable.

Everything from season 1 forward can be transmogged.....but the pieces themselves are spread out ridiculously in some cases.
I've noted which of the sets aren't the "main" sets from their season, as they do not have weapons to match and sometimes lack offpieces. The ".5" sets are slightly under the season's tier in quality, which only matters now because that's what they were called.
Main Pieces
Season 1: Gladiator - Area 52, Netherstorm (honor)/Isle of Quel'Danas (tier 4 tokens)
Season 2: Merciless Gladiator - Area 52, Netherstorm (honor)/Isle of Quel'Danas (tier 5 tokens)
Season 3 (blue): Stalker's (for hunters; other names vary) - BC rep vendors (gold) (exact duplicate of dungeon 3 set)
Season 3: Vengeful Gladiator - Area 52, Netherstorm (honor)
Season 4: Brutal Gladiator - SW/Org (honor)
Season 5 (blue): Savage Gladiator - Faction Vendor, Dalaran (justice)
Season 5 (".5"): Hateful Gladiator - Faction Vendor, Dalaran (justice)
Season 5: Deadly Gladiator - Faction Vendor, Dalaran (justice)
Season 6: Furious Gladiator - Faction Vendor, Dalaran (justice)/Argent Tournament, Icecrown (justice)
Season 7: Relentless Gladiator - Faction Vendor, Dalaran (justice)/Titan-Forged shoulders (same look) - Wintergrasp vendor (honor)
Season 8: Wrathful Gladiator - SW/Org (honor)
Season 9: Vicious Gladiator - Not currently available (applies to both the season 9 and season 10 colorations)
Season 10: Ruthless Gladiator - SW/Org (honor)
This is the confusing part, as early off piece matches were differently named:
Off Pieces
Season 1: General's/Marshal's (level 70 versions) - Not currently available (and according to that blue post, will be rating restricted)
Season 2: Veteran's - Isle of Quel'Danas (justice)
Season 3 (blue): Stalker's (for hunters; other names vary) - instance drops (same as dungeon 3 offpieces)
Season 3: Vindicator's - Isle of Quel'Danas (tier 6 tokens)
Season 4: Guardian's - SW/Org (honor)
Season 5 (".5"): Hateful Gladiator - Not currently available
Season 5: Deadly Gladiator - Wintergrasp vault drops (Emalon)
Season 6: Furious Gladiator - Wintergrasp vault drops (Koralon)
Season 7: Relentless Gladiator - Wintergrasp vault drops (Toravon)
Season 8: Wrathful Gladiator - SW/Org (honor)
Season 9: Vicious Gladiator - Not currently available (again applies to both colorations)
Season 10: Ruthless Gladiator - SW/Org (honor)
Bear in mind that some of the weapons do not match their season's armor visually.
Weapons
Season 1: Gladiator - Area 52, Netherstorm (honor)
Season 2: Merciless Gladiator - Area 52, Netherstorm (honor)
Season 3: Vengeful Gladiator - Area 52, Netherstorm (honor)
Season 4: Brutal Gladiator - SW/Org (honor)
Season 5 (".5"): Hateful Gladiator - Not currently available
Season 5: Deadly Gladiator - Not currently available
Season 6: Furious Gladiator - Not currently available
Season 7: Relentless Gladiator - Not currently available
Season 8: Wrathful Gladiator - SW/Org (honor)
Season 9: Vicious Gladiator - Not currently available
Season 10: Ruthless Gladiator - SW/Org (honor)
Whew! Just ran around checking all that in person. Hope it helps!