Griffin Technology, Inc. posted a beta version of the iMate driver for OS X today for their popular iMate USB to ADB adapter. The driver can downloaded free from Griffinis web site. The new driver supports all currently available ADB drivers including the Kensington Mouseworks driver for OS X.
For the first time ever, ADB devices are completely hot pluggable as the iMate OS X driver loads custom ADB driver even when connected after startup. Under OS 9, ADB devices had to be attached during startup for custom ADB drivers to load. The driver also supports multiple iMates. You can now connect several iMates to a single machine and each will provides a separate ADB interface that can load custom drivers for any devices that are attached. This provides for the possibility of being able to connect over 800 ADB devices to a single computer.
The Griffin iMate is available for US$39, and the iMate driver update is available for free. You can find more information at the Griffin Web site.