I agree, don't cut your case! You can mount the SCSI card reader internally in the HD spot, although you wont be able to install a floppy drive in the location just forward of the HD mount.
I have been working on my A3K, although this is not its permanent spot, you can see the SCSI card reader in this photo. They work very well and it is very fast on a stock 3000.
What brand and model is your SCSI card reader. I need to get me one of them.
