Acuminata Narrow phyllode will do fine zone 7b and up just make sure to keep it in a greenhouse the first 2 winters of its life and get something to wrap the trees in during frost after that if you notice any dying foliage. Frost cloth is available many places and is suitable for small to juvenile plants.
Over the years I've been able to test Acacia trees out in various climates and since I posted on here last, climate change has rapidly accelerated.
The 3 combined factors that make these trees struggle are Wet/Cold/Wind. Usually they are able to make it through each element by themselves but the combination of windy rainy cold spells for extended durations will cause problems for the health of the plant. There are ways around this. Staking the plants up, wrapping the plants, over wintering in a greenhouse, inside by a window or bringing them indoors during snow will buy them more time and increase longevity.
Sometimes they will die back to the ground and resprout in spring. It's important not to baby them too much, they're more resilient than one might imagine. This has just been my subjective experience growing them in Zone 7b, 8b, 9b, 10a.
The top Acacias that can withstand temperatures down to 15F or lower are:
Acacia Baileyana
Acacia Boormanii
Acacia Covenyi
Acacia Dealbata
Acacia Decurrens
Acacia Implexa
Acacia Melanoxylon
Acacia Mucronata
Acacia Pravissima
Acacia Rubida
Acacia Saligna
Additionally these may perform well but I have not gotten to fully test them:
Acacia Acinacea
Acacia Alpina
Acacia Angustissima
Acacia Burkittii
Acacia Cardiophylla
Acacia Constricta
Acacia Farnesiana
Acacia Fimbriata
Acacia Hemiteles
Acacia Kybeanensis
Acacia Longifolia
Acacia Mabellae
Acacia Obliquinervia
Acacia Pataczeckii
Acacia Phlebophylla
Acacia Riceana
Acacia Rigens
Acacia Terminalis
Acacia Verniciflua
Acacia Vestita
Acacia Xanthophloea(if protected from the rain)
Many can grow and thrive far outside their natural range but life expectancy may be greatly reduced or you'll end up with some super strong trees.
(picture is Acacia Mucronata in Zone 7b West Coast,US currently growing wonderfully through November nights in the 20s*farenheit* and did fine down to 15F with snow etc the previous seasons.) edit: idk why the picture became sideways after uploading but here it is