Mega 22/45 motor would be a SWEET solution.
The 22/45/2E is 950kv. That works out to around 23K RPM on the prop when running 8S. That may be good for 230mph airspeed.
If you're looking for the ability to run between 6S and 8S, and not be locked into 8S as the bare minimum, a bit higher KV may work out better than the 2 turn.
22/45/1.5SE comes out around 1225kv. This would get you around the same RPM on 6S. But if the motor's cool on 6S and you have a mind to run higher voltage, you have the freedom to move into 7S or 8S.
... and then there's always 22/50 and 22/60 motors