Ah heck. Decided to try them
The cable is definitely the shorter one like with the HP200, with the extension as well.
I admittedly like the flat black cups better than the disco mirror ball ones I've seen in pictures of the HP100. They definitely would show wear less if scratched or scuffed, and of course they won't blind anyone and cause any accidents.
First impressions after an hour of burn in is that the sound is definitely very linear (to be expected). Reminds me most of the Sony MDR-V6 I have in that regard, albeit with better subbass extension, better soundstage, and just better overall resolution. In fact, I am very impressed with how they render distortion/fuzz with guitar. The guitar in Smashing Pumpkin's Quiet sounds fantastic. Likely the combination of having a fairly smooth response through most of the frequency range (even though it has a dip) and good impulse response. Bass on EDM seems like it might be accurately represented--enough punch when required by the original recording. Imaging seems a bit better to me than the K550s (although I have not directly compared them).
Could this be a different driver that simply improves a little on what the HP100s already do? Sorry I can't tell you. But so far, they do so very good. I will probably end up keeping them.
So which one of you HP100 owners wants to buy a pair to see if they sound the same?