I use an iMate to connect my Extended II to my Powermac G4. I recently replaced the battery to be able to turn on the computer. I appreciate the traces, but I actually thought this was all well known. I use the G4 every day to make music and for recreational programming. I've also got an older Powermac which I enjoyed more precisely because of the Extended II[0], but the G4 is much faster so getting the iMate working was great.
Also, on Mac OS 9, the iMate doesn't just allow the use of ADB keyboards, but as far as I know actually acts as a proper ADB bridge, so dongles, modems[1] and other ADB peripherals work as well.
[0] It's like having sunshine in your fingers!
[1] Yes, there were a few ADB modems, and yes, they were slow.
Also, on Mac OS 9, the iMate doesn't just allow the use of ADB keyboards, but as far as I know actually acts as a proper ADB bridge, so dongles, modems[1] and other ADB peripherals work as well.
[0] It's like having sunshine in your fingers! [1] Yes, there were a few ADB modems, and yes, they were slow.