If you want to use that many devices, then maybe it's time to move to SCSI. A dual-channel adapter gives you seven devices on a 40 MB/s peripheral bus and up to 15 speedy devices on a fast 160 MB/s channel. With LSI Symbios SCSI adapters, pile up as many controllers as you want, they'll all be managed by one single SCSI BIOS.
Multiple IDE controllers will also work, but each of those will load its own BIOS into upper memory where you will run out of space sooner than you think.
regards, Peter