I have repeatedly overwintered E. globulus on a sunny, south side of the house. I also can 'get away' with loquats, pomegranate, and Podocarpus (must all be zone 7b/8). I should do more Eucalyptus though myself as I suspect deer will never eat them--they love loquats unfortunately.

I'm ultimately a fairly "cold" z7 but that's good information.

Expect even the hardiest euc to be cut back to the ground by winter cold periodically. Even in my very mild Puget Sound locale, every 10 years or so we get an arctic front through that will kill very mature eucalyptus back to the roots. They may survive - not always - but top growth is gone for sure.

Last time these got hit hard was 2 Novembers ago when temperatures plummeted from a record high to a record low in less than two weeks. I've attached a pretty interesting article about cold hardy eucs written by a friend of mine that is a eucalyptus growing specialist. Lots of interesting info to those who like to push the hardiness envelope :-)

Here is a link that might be useful: growing eucs in colder climates

Hardiness zones are soooo complicated. Surprised that Eucalytus can get killed down to the roots in Zone 8 PNW. Sometimes, this lack of winter hardiness is due to lack of SUMMER heat. Maybe it's the stronger winter sun, despite the colder Winter temps--? I was surprised though that Eucalytpus will often not only survive but remain evergreen in Eastern zone 7b microclimates.

I know of a Eucalyptus debeuzevillei type growing in Mass. IF you do try it, keep it out of the dry winter winds, and hope for good snow cover. I know some species will come back from roots.