Nice to hear about the Eriobotrya japonica trees doing well in zone 7(a). Some resources say that they are just hardy until zone 8(a), but I think older plants will be hardy until Zone 7.
The hybrid called Eriobotrya 'Coppertone' is a hybrid between Eriobotrya deflexa and the Indian hawthorn (Rhaphiolepis indica), so not a true Eriobotrya. Coppertone is said to be cold hardy until Zone 8a, but the advantage is that the bloom is in spring. The fruits are also edible. E.deflexa is a really bad crossing partner if you want a cold hardy hybrid, because it is distributed in warm zones like 9, 10 and 11.
https://books.google.at/books?id=rXTGyOlDjdoC&pg=PA515&fbclid=IwAR2gcYSS6BvPlgO1ytIFTjMpiw5bpHaxV-DJD_yWYoyHLE0rgRwb_1eYQlU#v=onepage&q&f=trueSome also say that Coppertone is a hybrid between E.japonica and Rhaphiolepsis indica. (What would be a bit better, because E.japonica is hardier).
Rhaphiolepsis indica itself is hardy until zone 7(a) or 8(a) (statements vary).
All a bit cold hardy, but nothing really hardy. A Coppertone hybrid (with E.japonica in it) could be worth a try. But if we could get our hands on species like Eriobotrya fragrans, elliptica or hookeriana, that would be a real game changer.