Don't mean to direct you elswhere, but the G4's are easy to upgrade yourself. I purchase my HD's and ATA interfaces from ClubMac. Wish I had one of those new machines.
I have my G4-400 AGP set up as follows.
OEM 20G with OS9.2.2
30G Maxtor on internal ATA bus with OSX 10.2.1
Sonnet Tempo ATA66 card with: 2 60G Maxtor and 2 30G Maxtor drives.
I use Digital Performer 3.1 (just updated from 3.02) and assign tracks equally amongst the 4 drives attached to the ATA66 card.
Had I to do it over again, I'd use either an ATA133 card (wasn't available when I purchased) or an ATA133 RAID card. That keeps the buffer issues in check.
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