Check PowerPC HDD for faulty sectors I have a iMac G4 that doesn't boot, so I'd like to check the HDD for faulty sectors.

Are there any utilities featured on the Leopard installation disk I can use for this purpose? For instance, can dd be run in any way to report all faulty sectors?

Alternatively, are there downloadable binaries for PowerPC that can do this? I have TestDisk for PowerPC, but I don't know if it does sector testing. I can't find it anywhere in the menus, at least.
There are no utilities on the install disk that can help you. The "SMART Status" that is shown in apple's Disk Utility is completely useless. VERY rarely have I had a failing drive actually indicate it is failing in Disk Utility. 

The best app for this is a utility called SMART Utility. It's not free but does have a free demo. They have an older version available that runs in 10.5.8 on PPC. You can get it here:
https://www.volitans-software.com/apps/smart-utility/

That will tell you if you have any reallocated bad blocks without needing to scan the disk. But you will have to have 10.5 installed on some volume and working in order to run that. Which means another internal drive or maybe a Firewire drive, or possibly a USB drive but that might not work. 

As a mac repair professional, it is my primary tool for diagnosing failing hard drives. 

If you want a utility that does actually scan the entire drive, I've found the best utility for that, believe it or not, it SoftRAID. Even though RAIDs in OS X these days are a whole big bundle of problems, that utility has a couple of different full-disk scanning and verifying tools that work very well. Although like I said, I almost never run them because SMART Utility is sufficient. Also SoftRAID is not free either although it also appears to have a free trial.