A Rev 1 would be a decent OS 9 machine even with the stock 6GB HD. I picked up 2 B&Ws over the years and both are revision 2's which also have room for 5 HDs using a single and two dual drive trays. One of mine has a G4-450 installed the other is a 400 both with Radeon Video cards and 1GB RAM. They are very nice machine and would make a decent vintage low power server if you need one. If you are worried about the Rev 1 IDE bus I suggest you get a mac rommed SCSI card and go SCSI for the HDs and you will not have any issues. There are some great deals on PCIX SCSI cards that work in Apples on ebay from time to time, or just older Adaptec PCI cards that are dirt cheap now (same with ATA/66 PCI cards).

Since the B&W has hit the worthless stage and is now going up in value as a collectable you should try pickung up one now before they get harder to find. I got mine a few years back during the worthless stage and have moved on to G4 Powermacs for utility work these days (since they are in the worthless for main machine stage).