I just released VueScan 7.0.22 for Windows, Mac OS and Linux.
It can be downloaded from:
What's new in version 7.0.22
* Added full support for USB scanners on Mac OS X
* Improved memory usage on Mac OS X
* Added HP 7400C support for both CCD sensors
(600 dpi and 2400 dpi)
* Added 645 film format (6x4.5 cm)