Obviously is has to be in Germany, Ottke wouldn't fight elsewhere. Therefore my pick is Ottke (Hopkins gets DQ'd for using foul language or landing a punch or something).
Ottke would probably "beat" him in Germany. He's underrated generally. Sure, he should have a few L's against his name, but people talk like he's a bum. He's not. He was very crafty and cute, which is why he remained so competetive despite having no power or any incredible attributes.
young hopkins workrate, stamina, and accuracy would overwhelm ottke into not coming out of his corner in the later rounds
Hopkins, no sweat, in Germany, Las Vegas, wherever. Ottke was a good fighter, Hopkins was a great fighter.