II found that newegg has kingwin IDE to SATA adapters that had good reviews....
The hard drives plus adapters won't fit in the original space - period. I probably should've known this but I thought there would at least be an inch... not so much.
There are other adapters which fit in the original drive space just fine. I'm using several on a few different G4s.
So I decided to run the G4 without an optical drive. This setup is working fine - and the adapters make the drive show up as an IDE drive (!) complete with SMART reporting.
Speeds aren't record breaking though. I ran xBench to a tune of 12MB/s. Sucky, but i figure there's loss in translation.
There's no discernible loss in translation, as you say. I have SATA drives on IDE busses that average 70 MB/sec. The IDE bus for the optical drives, if I remember correctly, will only do multiword DMA mode 2 which is 16.6 MB/sec. The main IDE bus should be noticeably faster.
