HD630VB & HD380pro (recently discontinued, that's 380, not 280), if I recall correctly, but not by much.
The one with the most impressive soundstage I've ever heard so far is MDR-7509HD (not to be confused with the non-HD version, it has V700 drivers), but it needs a lot of modification. There's woefully insufficient acoustic dampening in the cups for starters, and the need for lots of Dynamat all over, including inside of the hollow spaces inside of the headband forks/gimbals that connect the headphone cups to the headband - the whole headband conducts sound too effectively between cups. If you mute or disconnect, say, the left channel, the right channel will echo loudly through the headband and into the left cup, so you still get sound out of the left side even though you muted/disconnected the left channel! Stuffing the gimbals with Dynamat alleviates the issue completely, and then the soundstage becomes ATH-AD700-tier, seriously.
Then there is a ridiculous frequency peak at the top of the midrange and another at the bottom (mods or not).
Then it has recessed bass, like MDR-1R, though with even less extension.
If Sony re-released it with its issues fixed and bass boosted, it would potentially be a popular closed-back in the $200 and under range, maybe even catch on with gamers for its massive soundstage. It has big 50mm drivers with potential, but the overall design has too many critical flaws.
MDR-V55 is a potential successor, the drivers are very high fidelity for the price, but you have to unleash their sound with Brainwavz HM3 earpads (not HM5, they're too big), but then the severe issue with the driver tuning becomes apparent: three gigantic 18dB peaks span the whole treble range, it's ridiculous. I couldn't figure out a way to tame those peaks without drastic EQ, the headphone is really tuned for its stock earpads with tiny openings for the sound to reach one's ears, but then the overall fidelity is bottlenecked significantly.
I do not remember how well V55 does at soundstaging with the change in earpads, but the tuning needs serious work in order to take advantage of how good those drivers can be with different earpads, lol.
I don't know if anyone here cares for MDR-7510? I found it unimpressive. I doubt it is using 7509HD drivers, not high fidelity enough.
Now that I double-check, Momentum On-ear/HD1 on-ear/Momentum On-ear M2 has wider soundstaging, but it is not as high fidelity as HD8 DJ. Forget the XL version, it comes with much more drawbacks to the sound than improvements over the smaller on-ear version, including narrower soundstage for some reason.
Then there's DT770, but that's apparently not worthy of this lounge, heh.
/end rant