Dear melita2,
melita2 wrote:Does any version of Silverfast work with a Powerlook II linked via a SCSI to USB cable to an upgraded G4 running OS X 10.5?
No, SCSI to USB converters are not supported by SilverFast.
melita2 wrote:I can't find any references to this scanner being supported on any OS after 10.3. Can anyone help?
Mac dropped SCSI support from OS 10.3.8 onwards. There are only two SCSI cards manufacturers which are compatible with the latest OS X (10.5 and 10.6) which are ATTO techonologies and ACARD. Those cards cost about 500 dollars and I am not sure they are compatible with a G4.
In such cases it might be worth considering replacing the scanner itself.
Cheers