The ideal reallocation would be to a US air base - kind of narrows the choice - Ramstein (for aircraft deployed into spare HAS in crisis) or Lakenheath (for F-15E now - F-35A later) - there are plenty of spare WS3 slots around (100 at Lakenheath alone) that could be up and running pretty quickly.
Wasn't it stated on another thread that F35 is not nuclear capable, hence the Germans had to reject it as a Tornado replacement?