My apologies if this has been answered elsewhere.
Steve's first look for the Sony Alpha states that KM's 5600 and 3600 are compatible with the Alpha, but are Sony's HVL-F56AM and HVL-F36AM backwards compatible with the 7D? I imagine they might be the same flash units as KM's, but you never know. If they are compatible, then that should help solve the availability issues.
No one will say for certain, but they appear to be re-badges Minolta units. There is no reason to believe that they are not compatab;e. You can always get the Metz for around $350.