It's good to know, what's coming - I just bought a pair of Fostex T10, they're on the way. I also own a pair of Yamaha HP-2 and I find them rather complete even if a little dull (although I may as well say "forgiving").
In the meantime, I just got a pair of 1971 Koss Red Devils, they seem to be a rare bird even in the US, let alone Europe.
All I had to do was replace the foam in the cups, which mutated over the years into something sticky and almost fluid. I added one cotton disc (makeup removal type) in each cup, placed a thin layer of fabric (I'd torn it off some ear cushions I had laying around) under the Koss's ear pads, covering the aperture and I also cut a rubber ring out of a regular computer mouse pad and put it on top of the cloth and around the "knob" through which the sound actually comes out from the speakers.
These simple manipulations subjectively made the red devils sound milder, removing some harshness from upper mids and adding some focus to the lower frequencies without taking too much weight off them.
A rather enjoyable pair, I'd say...