Well if you're that concerned about the explosions and rumbling, the Senns would probably please you a little more than the AD700. However, the difference wouldn't be substantial. If you sprung a little higher for the Denon D2000 on...
I would also be afraid to whip out some of those you listed on a train. Too fragile and big. I'd go with something far more durable and compact like the Shure SRH840/940 or ATH M50.
I've come really close to buying a HeadRoom amp many times as I really want to try their crossfeed. I think I would really enjoy it for a lot of the jazz I listen to it. HOWEVER, as some have already mentioned, I feel they are just way...